BIAB two bar endings are set. There is really nothing you can do with those. With RealTracks, there is an option to have those play for 4 bar endings but still it is a 2 bar ending that RT expands on.

However, you can use tags to do all that you want. For example, your song can be three choruses and have a tag that repeats any number of times and then fades out or uses the standard 2 bar ending. Read up on tags and fade outs. Fairly simple once you grasp the concept.

R