I set up a BBC ganging for my wife for a trip we took to Memphis TN for a basketball game. I posted an ad on Craigslist and spelled out that I was doing. I went through all the replies and picked out the 6 or 7 best replies / biggest dicks. We only wanted about 4 guys, but I figured I needed to get about 6 or 7 interested as I knew at least 2 would probably not come through... and I was right on the money.
Communication, as Mrs.InCharge mentions, was key as you need to start this well in advance of the night you want it to take place and you need to make sure everyone is still on-board with the plan.
The night of the event we had all the guys meet us in the hotel lobby bar for a few drinks and some ice-breaking conversation. We headed up to the room first and about 5 minutes later the 4 guys arrived.. my wife was dressed sexy and ready to go. All 4 guys were eager to get on the bed with her and the next few hours were A LOT of fun for all.
Good luck, have fun, be safe, and take pictures...