IMHO, if you really want these cameras to sync throughout your program you should run reference and timecode to each. The AJA Gen10
http://www.aja.com/products/converters/converters-hd-gen10.php has multiple outputs (so no DA is needed) and will generate SD or HD sync. If the cameras don't accept sync, use Rick's approach. Since you have three options when you cut, you can always adjust for drift, but once you start slipping or sliding tracks, you'll lose the speed of synced multitrack editing.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.5 QT7.5.5 Kona 3 Dual Cinema 23 ATI Radeon HD 3870
ATTO ExpressSAS R380 RAID Adapter, PDE Enclosure with 8-drive 6TB RAID 5
24" TV-Logic Monitor
Final Cut Studio 2 (up to date)
Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN
