One bodhran good. Two bodhrans at once - well maybe. Three bodhrans at once, head for the bar or the tent. The thing is, if the fellas know how to play, they'll know to take it in turns so there's never any more than 2 at a time. And if three fellas who don't know are playing at the same time, that's no place to be.

Mind, you can say almost the same with guitars. Except that there are probably more ways that guitars can be played alongside each other without interfering with each other. Can be played, I said.