keymaps would be the solution

create a keymap for your main that would change the key assigned to your G key (like LSHIFT+LCTRL+F to G5) into a hotstring (like heal_main). repeat for all the key combinations you create/assign to the G15.

save the keymap
load the keymap on your main via keyclone (right-click on it's entry in the keyclone list to find the 'load keymap' command)

then on other clones, create and load another keymap that will change the appropriate hotstrings (ie: heal_main) into a key (like F3). keep in mind, if you don't provide an entry for a hotstring, it will be ignored by that clone (IOW, it won't turn into a key and just get dropped).

and yes, override is how you stop keys from being broadcast... which you want when you stop to chat with someone. just adding your chat command key on the do-not-pass won't help... as every key you type in the chat window will be sent to the clones. (and make them do all sorts of odd things)