What's the best plan for multi-ownership?

[Fishboy]

My siblings are recommending we enter a collective agreement to purchase property in two different states. I realize I should consult with a real estate attorney and I certainly will. Before I get in to this, though, I want to ask here for an opinion. What's the best way for four people to own a single family residence?

Aloha pumehana,
Brian and Mary
Lynnwood, WA\Discovery Harbour