Bi-directional firewire or other alternative

my night gig is teaching a studio production class for the art institute. they just bought us a new MacPro for use in the studio as a playback system. Basically, we connect the ethernet for the LAN and students can export their videos from Final Cut to the mac in the studio for playback with the studio system. The mac in the studio is connected to a Sony DSR-1800 via firewire 800-size 6. However, the studio is also configured with a DVCPro HD VTR to record the show. The DVCAM is for playing back content. Even without genlock, framesync & a TBC the video from the mac through the DVCAM deck will play fine, but is there a way to simultaneously play out content as well as record content on another FW800 port? Can FCP 7 be used to playout video from the timeline/enternal video all frames and then use Quicktime to record the signal from the DVCPRO VTR at the same time. Or do we need something like a BlackMagic card or AJA? Thanks