I came across a great blog post this morning at Inkling Markets where Nate makes a great point-- Enterprise 2.0 - Tiger Woods would kick your ass with 3 golf clubs:
Tiger Woods could walk into Kmart, grab 3 clubs from the cheapest, shittiest bag of golf clubs in the store and still kick your ass on the course.
If you're having trouble getting people to work together no tool is going to fix that. People who are truly motivated to work together will find a way to get it done no matter the tool. If your groups are not working together now they're never going to work together unless you solve your people problems first. Before you spend a ton of time and money on technology-- invest a lot of time in conversation.
Because it's not about the tools.