I really can't give you advice about how to go about doing it [kindly dumping one of these guys].
However, if you adopt a new strategy, it should be easy:
- find a new FB, could even be one of us massageplanet dudes, hehe
- keep your rotation of FIVE for a month
- dump the guy who is the "lamest", use what ever criteria you wish
- do this every once in awhile, say every month or two
- repeat, and make it a process
You will always have the best set of FBs around, and you'll have no problems dumping anyone of them in the future.
Maybe not the same analogy, but what process do you think us hobbyists go through?