Occasionally, I want to have a Realtracks solo over an intro, or lay fills on an held note at the end of a phrase. I find hitting the "Soloist" button and opening the Dialog allows for a "Custom" choice of specific bar ranges. I generate the Realtracks for say 4 bars, and then repeat for one and two bar fills additively. This is easy with Real Band, but for "quick and dirty" BIAB generation, I find it works pretty well..

Jan - 12 Core AMD Ryzen 9 3900X
Win 10 64-bit
Samsung m.2 SSD Boot drive,other SSD internal and USB drives.
Ketron SD4,SD1000
Yamaha RX-v381amp
VB-Audio virtual cables