Hookpad - entering passing bass notes

I’m using Hookpad to enter the chords for Eagles “Wasted Time”. The intro has an Fm chord that plays on beats 1, 2 and 3. Beat 4 has two eighth notes that are Fm/Bb and Fm/Ab. Is there a way to get Hookpad to play this combination? If there’s a theory rule that applies to this, I haven’t been able to figure it out. The song is in the key of C, so Fm is already a borrowed chord. I tried to figure out if there is an inversion that fits the Bb and Ab, but no joy.