Own code: changing settings using button menu

I have a set of 3x nodes Base, Repeater and Remote, toggling gps backwards and forwards.
The base has a log serial adaptor.
I wanted to carry out range tests, and wanted to be able to turn up and down the range settings, using a button press menu.
I almost got it to work by sending messages, but couldn’t get it to work because once one node changes then it’s out of the link.
Bear in mind loss of signals if you think about this!
C