Instrument changes with a constant mixer setting

I understand that Instrument text allows midway change of instruments on one staff. It seems to me that Musescore wants to make a new mixer channel everytime you switch the instrument. If I have an electric bass staff, and I want to switch from regular electric bass to slap bass and back again multiple times, I only want to utilize two mix channels, namely, the regular bass and the slap bass. Is this possible?

I realize a workaround could be to have two separate staves for slap and regular, but that's sort of ridiculous if you're signifying for one player to do a certain technique. The only workaround with that would be to have both staves working and notate with them, but then copy the slap notes over to the regular bass staff, then make them not playable and put "Slap" technique text on them and then hide the slap staff. It's viable, but if possible I'd rather have instrument changes (rather I'd call them change to particular available instrument in mixer) between two mix channels over and over again.

Is there any way to utilize the instrument change to go back and forth between two channels and only two channels instead of each time an instrument change occurs to have a new channel pop up? Am I not understanding something?

Any help appreciated.