Even if its not computerizeable(and I see no reason why its not aside from labor), there's really no reason why a faction shouldn't be allow to register multiple tags...Only in the case of factions being below the minimum hours is it really an issue, and all a faction would have to do is point to 1: the fact that they've registered as using X} and Y) and that together, X}+Y) are enough to satisfy activity.
So I think this should be reasonable and acceptable.
Of course, I'd suggest no more than..three? Tags per faction..just so being able to identify people ingame does not get insanely difficult.