Late, but another way to get around this is to simply split your group 3/1 or 2/1 after getting the Drudaene from the Lizard thief. Convince him with Red Prince to hand it over promising to protect him, send back your weakest member(I sent the female elf rogue type), then once you talk to The Gang & turn him over, you jump cam back to the other members & kill the assassin sent (Be careful to use NPC specific skills, or the Lizard will become hostile if hit). He'll offer you compensation for saving him, & the Gang seems none the wiser.
