Rockbandguy, you have stumbled upon my biggest peeve about BiaB. If you stay with 3/4 or 4/4 then BiaB plays well with other software. But with any other time signatures it does not. All of my other music software plays well with each other, BiaB is the only one that does not play well with them.

You really have two good (or not so good) options. A, do everything in BiaB. That means you can not add a 6/8 time signature from other software to BiaB. B, create a 6/8 time signature in BiaB, drag and drop it into your DAW, then play the other tracks yourself. Yes there are other workarounds like have been mentioned but they are a PITA and really take 6/8 feel out of the song. YMMV

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware