I wore a bug team down with Nightsisters (zzTalzin, zAV, Daka, Talia, Zombie) without too much difficulty. Let Plague and AV's AOE wear them down a bit, then nuke one with MT's full team attack. Repeat until deaded - it's slow, but it goes much faster once you manage to get one down.
Granted, this was with full G12 sisters (minimal G12+ gear, all modded for around 75-85 speed) against like, G10 bugs with "meh" mods. Dunno if it remains viable with equal-geared and better-modded Geos.