Branching with TFS 2010

[JenSRA]

We currently have a need to work on four different projects/source branches at once. We need to be able to check in our changes to multiple sources in TFS 2010 so that the changes to these files perpetuate forward (so if you make a change to Project 1, it also perpetuates to Project 2 and 3). We can't figure out how to do this, which is a huge problem. Ideas? How does one handle branching, if at all, in Flare? Or, I've been reading about global project linking...does this even work with TFS?