You can run the speakers with the normal AC ground connection. The concern with most bridged amplifiers is that neither speaker terminal is at ground, so if you connect into a setup that does have one terminal grounded, a potential (pun intended :) exists for damage to the amplifier. The AC ground of your ESLs should have nothing to do with this. I've not heard of an ESL where the AC ground is the same as the '-' speaker terminal, but I suppose it could exist. Check with the manufacturer to be sure.
What ESLs are you using?
All the Best!
What ESLs are you using?
All the Best!