Based upon Mixpad documentation and tutorials, AI gleaned this info. It's not guaranteed 100% accurate but may provide insight...
"MixPad does not have a traditional "track grouping" feature like some DAWs where multiple tracks are combined under a single volume fader. However, you can work with grouping patterns on the same track, and MixPad offers a Group Effects feature that allows you to add effects to multiple tracks collectively.
For managing the volume of multiple drum tracks (kick, snare, hi-hat, ride, etc.) as a single unit in MixPad:
One workaround is to route all drum tracks to a "Group Effect" bus where you apply volume control and effects collectively. You create a Group Effect from the menu: View -> Group Effect -> Add Group.
Another approach is to manually adjust the volume sliders for all the individual drum tracks simultaneously or link their volume controls if available.
You can also rename individual tracks (double-click track name or use the Track menu) to organize your drum tracks clearly.
Patterns on the same track can be grouped for editing but this grouping is not the same as group volume control across multiple tracks.
To summarize, MixPad does not feature explicit track grouping to create a single slider for volume control of multiple separate tracks like the whole drum kit. Instead, the Group Effects feature or manual volume adjustment is used for collective control. If you need comprehensive group mixing, a DAW with dedicated group or bus track features might be required."
For more, contact NCH.