(edited by pimie.2463)
Binding a key to mouse 1 and mouse 2
Your mouse program may have ways to assign the RMB and LMB to other keys, possibly. I’m not sure there is a way to do it in-game. Or maybe a Windows feature. You could try Googling it.
Good luck.
You can assign secondary key binds to certain actions, that should include the default assignments for MB1 and MB2.