From what I understood, you want to spawn a camp randomly at one location out of three? There's a few ways of doing this, some are:
Build three camps, name all the objects, and delete the ones you don't need after you've selected the camp location.
Using the camera.sqs, take location coordinates of buildings and tents for all three camps, then setpos the stuff at the camps. You can setdir the stuff to face the right direction.
Make three gamelogics at the center location of the camp and setpos/camcreate the objects around the gamelogic and then setdir them. Personally, I wouldn't use this option.
Just a few, there's more I'm sure. I would love to make an example mission, but I'm at work ATM so that's impossible. I don't think my boss would be happy if he saw OFP on this computer.