Changing a repeating resource through macros or API

Is there an easy way that I can have it so that when a player clicks one of their traits, a specific repeating resource gets depleted by a certain amount?

I use the ammo api for that sort of thing.  While I don't have it automatic, I set up an ability macro on the sheet that will reduce that resource, and then add a chat menu button to the description of that trait/feat.  That way, they can roll/display it in chat without automatically reducing the uses if it is just being put up for display for some reason, but it just takes one more click of a button that is already in chat to reduce that resource.