You're looking for subversioning, but since filemaker isn't a compiled program built from code level files, it's hard to achieve.
This has been talked about in length before:
Long and short, the database versions in your repo will always be complete files. EG, some will have to write out "I made x changes to y script and z layout" because you can't subversion at the script, layout or schema level.
FileMaker can be placed in version control solutions, but most of the benefits developers expect from those tools don't apply to FileMaker files in them, as Mike explained. However, if the goal is simply to enable multiple developers to work on an application simultaneously, they can all just connect to the same hosted development copy. There are some things two developers can't do at the same time, e.g. two developers can't be in Manage Database at the same time, but this is usually not a problem. Developers collaborating on an application tend to be working on different things, and therefor infrequently step on each other's toes.
I find it invaluable to have my FDS version of FMS hosting a copy of any database that I want to modify. This way I can modify any aspect of a recently archived version and test it to my heart's content --- even to the extent of crashing the developing version, without corrupting the file.
Once the mods have been tested adequately, FMPA has the copy and paste capabilities to bring the changes across to the production version. Here the biggest challenge can be keeping track of which version you are copying from and which version you are pasting into. Having multiple monitors helps to keep the windows from overlapping.
I hope this methodology will add to the good advice you've had from Mike and Jeremy,