Can you use a group target, with personal range, to affect only a group you are a member of?
But sensory magic, HoH:MC bluntly contradicts this core rule.
HoH:MC p.27f Sensory Magic is a Mystery Virtue, which defines and allows spells with a new type of Target, and explicitly extends R: Personal for use with these new spells.
With this Virtue, the taste, texture, scent, sound or spectacle of a magus can magically affect those perceiving it. But this Virtue does not redefine or contradict ArM5 p.111 Ranges Personal of other types of magic than Sensory Magic.
Cheers
To add to what One Shot said,
- The results of Personal spells can affect others beyond the individual. For example, if you use a Personal-range MuCo(An) spell to become a wolf, you can bite with you magical wolf teeth. Or, closer to what we're looking at here, if you turn your blood into lava, that lava can harm those onto whom it gets splattered. Sensory Magic isn't so different from the latter, as it changes the species emitted by the caster/target somewhat like the blood splattering from the caster/target; it's just that Sensory Magic does it in a way well beyond what vanilla Hermetic Magic can do.
- Just because you can't have a Target greater than Individual doesn't mean you can't have other Targets. For example, Hearing. So Sensory Magic's Targets are consistent with the core book.
- Is there a better way to fit Sensory Magic into the existing R/T/D rules?
As to the OP, no, that doesn't work, as jason72 pointed out.
As said, no.
You can use Touch to affect a group - the whole group must be in contact, but you need touch only one member of the group. That's about as close as you'll get.
Thanks for the responses, I couldn't work it out.
It seemed silly, but I wasn't sure.
That's one of the things the forum is for.
personally I would see exceptions, even though written as RAW, to the idea that it must be individual (or smaller, obviously part would work). For example if I have range personal for a MuTe spell affecting coins, they could be targeted at a group of coins I am carrying. Spells involving clothing, or perhaps ammunition might also apply (facing a werewolf? convert your ammo to silver!) Maybe a PeAn group target personal range to eliminate lice...
Now that you mention it, how about this? You cast Cloak of Black Feathers on yourself and Inmost Companion on yourself. Now you cast a Personal MuAn spell on yourself to increase the Size of a bird, and you want it to work on both simultaneously. Would Personal with Group be used? Remembering back, that was how I thought things should apply in situations like the core book magical wolf if it could use other effects on itself while operating under Pack of One. Clearly I'm looking at fringe cases here.
would anything break if Per/Group spells were allowed, representing that the caster must be part of the group?
I don't think anything would break per se, other than getting a 1-magnitude discount on your group buff spells. You'd probably want to add a clarification that Personal spells still need to penetrate magic resistance on the rest of the group, whereas for yourself they don't.
Which is kind of similar to the discount you get on your Ind buff spells.
I used to find it a little counter-intuitive that Per range could not apply to Group target, but that magic resistance issue explains it all. Per range is an oddity in that it operates inside the boundary of magic resistance, and it would be hard to explain (even by magic standards) how it could then also operate outside the boundary and affect a group.
Similar, but I feel there's a notable difference between 'Anyone I touch grows tentacle-arms' to 'I grow tentacle-arms' vs 'any group of 10 I touch grows tentacle-arms' to 'any group of 10 I'm part of grows tentacle-arms'.
I like the above comment from loke above about inside v. outside magic resistance. You could track that while allowing for Personal Group. Then, for instance, since both selves are inside magic resistance with Inmost Companion, you could rule that Personal Group allowable. You could similarly allow what silveroak mentioned.
Theoretically, you could also cast a group version of a single-wound healing spell on yourself, couldn't you?
For the most part, why? If you're healing Light Wounds, you're better off moving from base 15 to base 25 to heal them all than using Group to heal up to 10. Same thing with Heavy Wound, moving from base 25 to 35. Even better for Incapacitating Wounds, moving from base 30 to 35. Now, maybe with Medium Wounds... However, in that case we should note that core ArM considers the lists of guidelines incomplete, so many SG's are likely to allow base 30 to improve all Wounds by two levels.
As far as 'why', I'm just making sure I have a good handle of how the system is laid out; An extrapolation on why a spell with personal+group would exist, and the since I'm playing a healer-style mage in my home game, that was the example I came up with as to a multiple-target-single-person spell would exist. If you have ten light wounds, you it is marginally easier to heal them all with a group-personal spell than Incantation of the Body Made Whole. 
I think you missed some of what I wrote. If you have ten Light Wounds or twenty Light Wounds or 100 Light Wounds, they can all be healed with a single casting of a single spell using a base that is 10 levels higher than the base to heal a single Light Wound. If you can heal an unlimited number of Light Wounds by using a different base with R: Personal, T: Individual, why would you make R: Personal, T: Group to heal only a maximum of ten Light Wounds with exactly the same level spell?