Ribbon - toggle button problems

[Bob Phillips]

I am trying to create two toggle buttons in a custom ribbon tab and make it such that:

1. When toggle button 1 is pressed, toggle button 2 is switched off
2. When toggle button 2 is pressed toggle button 1 button is switched off and so forth

Isn't a toggle button supposed to have two states itself, that is using one to control another is a tad redundant?