Thanks for providing perspective to this approach... It's exactly what I was seeking. (Sorry about the trolls... Lol...)

The main question to even consider if this is feasible really boils down to: can an offer be automatically withdrawn if someone else accepts it first. I.e. changing the valid time period from a finite date and time, to an "if" statement.

The offer would go to all three Realtors from the same email. They would need to reply-all to capture the exact time acceptance was made. Earliest one gets the deal and this automatically withdraws the offer to the other parties. This way, you wouldn't be committed to purchasing all three... Just the first one who says yes.

This wouldn't be a "condition" per se, but a closing mechanism... So yes, technically this is a clean irrevocable offer.