See if any of these help:
You can select bars and then drag export but that will give just that section of bars.
F5 mute @ bar 1, back to normal @ bar 9, mute @ bar 13
should give you what you need.
You can save the track as a Performance track then move it to audio to edit,
you can have another instance of biab and do the same, then you can copy a section out of that audio edit window and paste it in the other instance audio edit window.
"If I mentioned this in past, sorry I simply do not remember."
My memory is just as bad, maybe you asked this in the past and I replied with the same suggestion ???? crazy

MultiRiffs In Biab & Custom Track Sections Generation