Well, in Florida, you would have to 'sell' your properties to the LLC. That would require you to deed the properties from yourself to the LLC which means closing costs, as well as some tax consequences.
This might be a problem if you have mortgages on these properties. The lender must be notified any time you 'convey title' on the property to someone else.
What is the purpose of you guys doing this? You need to consider what happens when you all have different opinions of what to do with each other's properties. Owning a portion of the LLC, you will own a portion of it's assets and so will your friends.
Why not just set up an LLC and, moving forward, use it to buy houses.