Modding Help Assigning multiple abilities to weaponry

I believe this topic was brought up before, but I could not find the thread I saw it in. Does anybody know how to add an extra alt ability to a weapon? If anyone does, and wouldn't mind giving a brief description of how one can set up the proper files, it would be greatly appreciated. Thank you for your time!

 

The alt ability is tied to the right mouse button. You can't have more than one.

 

Super clunky idea: a "master alt" ability as the weapon's alt ability. Hooks into the fire() event, and then activates other abilities based on other keys being pressed. Kind of like a fighting game combo. If you're right clicking with S pressed at the same time, activate this ability, etc.