A few words catch Guillaume's attention and he focuses on Maurice's comments to Vibria. He doesn't get up, nor does he interrupt, but his interest is apparent.
"If you can do that, that might be best. Eliminates the Penetration issue, as you said, and might not be interpreted as an attack..."
[color=red]"Will you tell me her name, Maurice?" Vibria asks sweetly.
OOC: Do you remember your grandmother's name? Your father's mother? That is the name.
Esteban says, "This is a good plan. I have only one thing to add. I will lead the almogavers. We will await in hiding as near as possible. If negotiations suddenly take bad turn and you need to fight, the signal is to shout 'Fight! Fight! Fight!' three times in Latin. Then, everyone attack as fiercely as we are able." He shoots a glance at Maurice. "This is only a contingency, but we want no hesitation or misunderstanding if the critical moment should arrive."
Vibria gets a stunned look on her face, then grins broadly.
Marice responds in his friendliest draconic tone. I will gladly serve as liason. Simon will do as I tell him. My brother Venkath, however, he will be harder to keep under control but I am sure he is a wise serpent who sees the wisdom of planned coordination (Maurice is obviously trying to butter up his dominant brother and is suggesting he is wise and this is what a wise drake would do, and Vencath is prideful enough to fall for it).
Seriously, did you ever name her? I cannot remeber if you did, and if not you should name her now 
Let's go with València.
"Fair enough." Gardaitis hauls himself to his feet and wanders away from the fire for a minute, looking at the ground. He bends down and scoops a large stone from the snow: a moment of concentration (spontaneous non-fatiguing PeTe spell), and it cracks apart in his hands into neat equal pieces. He returns to his seat, handing a piece of stone to each magus. "I'll drop my piece just inside the door of the hut, so those of you skilled with Imaginem can listen in."
Vocis takes a stone and nods. Good thinking. I can keep an eye and ear on things and contact those who can't if and when the plan goes south.
(OOC - can I use Whisper of Divided Twins on these stones? The spell description is pretty specific about shells, so I'm not sure.)
When using a sense at a distance, the Target limits what you perceive, so, if using Target Room, you can't perceive anything outside the room.
This is why a spell like "To See as Though a Plethron Distant" use a special target (IIRC, Room +1) to be able to perceive things outside of any defined Room.
As I see it, Whisper of Divided Twins works because you speak "inside" in the clam shell, so is encompassed by the Individual Target of the spell, in part through the rule of "pretty minor special effect for cool, non abusive spell". But you won't hear what is said "outside" the shell.
With Arachné, I have a similar spell to use her Vision at a distance, so I used T: Vision (Note that it may be wrong, but it is 1 magnitude more than the RAW Room +1, so I figure it's at least right for numbers). I'd do a similar thing for other senses, mind you, such as T: Smell, T: Hearing... Using the higher target for multiple senses.
So, I'd say to use a touch range with duration and added magnitudes spell (Base 1, +1 touch, +1 Conc, +3 hearing = lvl 10).
Of course, those who know better spells (such as "to see" or equivalent effects inspired by HP) should use them 
(( OOC: I don't see why not, actually. Fixer's point about shells is a good one, but misplaced, IMO. Think about it -- if you're listening to what's inside the shell, you have to hold it up to your ear, at which point the spell that connects the two has to penetrate your Parma. So for the spell to work at all between two magi, the shell has to be close by but not actually held, which means the sounds have to be loud enough to be audible from a few feet away... so there's no need to use an actual shell. Any arcane connection would work.
I'd just go with InIm at R: Arc, personally. You don't really need two-way communication in this instance, you just need to see/hear what's going on inside the room. "Ear for Distant Voices". For that matter, you can forgo the arcane connection entirely with an R: Voice version of "Prying Eyes". ))
Gosh, why all the difficulty? Let's just do a R: Touch InIm spell on one of those going in before they go in. Just make sure it can handle the distance between you.
Parma. Unless y'all trust each other enough to drop it.
Maurice contemplates, smiles, and looks at you with deep introspection. València. Valerie València. And she loved grandafther dearly. But there came one sad day when she felt she had to depart, for it was what was best for her child, to be raised amongst men. She bore his son, whom I am now guessing was your father? Yes, that would make sense, and fits with the other clues.
We three, my brothers and I, are the offspring of the infamous Diablo Rojo, himself a Son of Sigmundo. Draconic lineages are complicated. Very complicated. Breeds and broods mix and match and intermingle. Diablo Rojo was a firedrake but had grown to become a true dragon of fledgling status, but he never progressed beyond a bestial intelligence. Our mother was a Fire Wyvern, not as strong or powerful, but posessing sentient intelligence. Grandfather stole three eggs from her clutch, with the assistance of Valerie València, your grandmother.
...
Brothers! Hark! I believe we have met a lost cousin! Permit me to introduce Vibria Flambeau, grand-daughter of Valerie València and our own grandfather the Dragon Sigmundo!
Venkath: growf?
Simon: Yay! Cousin! (starts licking your face like a happy and excited dog)
Carmen: This is much better. We are figuring out a plan. I propose we divide into three teams though. Vulcanus and Vibria will work with the drakes and form a perimiter but remain slightly out of visual range. Estaban and Alexandro will lead the guards to secure our flank outside the door, and the third groop enters the ruins of the old cottage on Bone Hill to investigate. I will accompany the rest and investigate the cottage.
Vibria smiles, feeling rather proud of the grandmother that she never really knew. ((Does she know aught of the Diablo Rojo? Int 1 + Magic Lore (Dragons) 5 + die roll of 4 = 10.))
Vibria hugs Simon around the neck and nuzzles, grinning and laughing.
When I get home from work tonight, I will have Maurice tell you the saga of Diablo Rojo. 
♪♫ Come and listen to my story 'bout a wyrm named Red
Poor firedrake, barely kept his hatchlings fed ♫♪