The /whatever note will generally only affect the bass track, if that helps.

In other words C/G will usually only cause a bass track to use the G.

The other tracks play the chords on the left side of the slash.

If you are trying to make a piano or guitar track obey this command, you'll likely find more success/joy by naming the chord differently.

I'd start with Ab2 and hope it worked. Getting to the level of control of dictating certain notes can be trial/error. Sometimes just expressing a different chord/voicing can work .. sometimes not.

Make your sound your own!
.. I do not work here, but the benefits are still awesome