Hmm. I plan to run two separate instances of bfgminer, where one instance would only control/probe for Erupters (-S erupter:all), and the other - only BFs (-S bigpic:all). Hope this works. If not, I'd need to plan for all BlueFuries running from a separate machine.
I think you should be able to run them on the same machine by specifying the serial port number (for com3 it would be -S //./COM3 on cgminer I haven't used bfg but guess it can also work without probing).