As far as I can make out, the assigned buttons are set to standalone (the apparent default setting), although I could not find any way of setting this, either thru the main menus or in the button properties window.

It recently occured to me that this capability might be a function of the T3's firmware which is currently version 1.1.0 and the most recent is ver. 2, I believe. I'm checking to see if a dealer can do a firmware update for me.