How about letting Aliens share frags, similar to the Human credits? Instead of each kill being worth 1 frag, it could be worth 100 frags. When the human dies, those 100 frags are split among the aliens who have injured him.
Of course, every class should have their fragcost multiplied by 100 as well.
To avoid having to redo the HUDs, you could divide the "real value" by 100 when displaying any frag or frag cost. This could cause a bit of confusion though, since you wouldn't see your frags increasing when you make a kill. Not sure how to "work around" that confusion (or even if a workaround is actually necessary, I doubt the confusion would be that great).
Chamooze
