Hi, Oldfinger (I'm sure that's not your real name):

It's possible to combine the staves using the Merge Staves option under the Staff menu. That might bring your parts back together.

I'm not sure how BIAB saves its tracks (even though I have the software). Perhaps you might upload an example file here so that we can see the problem.

It shouldn't be too hard to come up with a solution.

David