You may not be able to do this exactly in BIAB, but may be able to get some approximation. To hold a chord, for instance C7, enter "C7..." in the BIAB cell. To rest, enter "C7.". Now BIAB will only allow 4 chords per measure. So if you wanted to sound this as quarter notes on beats 2, 3, and 4 of a pickup measure, enter "C7.,C7..." in the first cell for the measure, then enter "F7...,G7..." in the second cell for the measure.

Now if you wanted this to "sound" as eighth notes, you could use "function-F5" and change the tempo of this one measure to twice the tempo of your song.

Bruce


Macbook Pro 2018
2.6 GHz 6-core Intel Core i7, 16 GB RAM
OS Monterey
BIAB for Mac 2022