MPC X - Track Mute Groups

I’ve had my X for a bit, but am trying to expand to use more of the features that I haven’t used until now. One of them is using track mute groups as a sort of de facto mixer to mute several tracks at once in various intervals and add variety that way.

I followed the MPC Bible instructions and.... nothing. In short, I added the pertinent tracks to group 1 in the track mute page (after making sure preferences had play and record track mute events checked)... then hit overdub/play and hit one of the pads where I wanted the mute to begin.... and nothing happened. The tracks didn’t mute in real time and nothing was recorded.

Any idea what might be up? Thanks in advance.

I don't understand why there is no info on this anywhere on the internet