Having just survived and come out partially scathed from a all-male triad that destructed like a nuclear explosion, I urge some caution. I like what one person said about doing a trial run. Basically move in for a short time...a few weeks, a month, whatever, but not give up your lease on your own place untill you know it's going to work well. Gay men can be more pig-headed than they let on at first, IMO, and you want to make sure there aren't these types of issues that just haven't come up before. Pay very close attention to the personality dynamics and how everyone meshes with each other. I've joked (though seriously) that in any group of three men, if more than one has "alpha-male" tendencies (and I'm not talking sexual), then you're gonna see heads butt like a group of irritable rams.
Personally, I wish you the best luck in this endeavour...I know another mmm triad in my town that seem to be doing great. But they are playing it more cautious---after a year, one still hasn't moved in full-time just yet. There seems to be no rush and I think it's helping them get acclimated to everything first.