Map screenshot to a controller button combo?

[bomblord]

I like to take a lot of screenshots while playing games in Dolphin but much more enjoy the "comfy couch" experience where I'm playing on a TV with my keyboard well out of my comfortable reach. This makes it difficult to hit he F9 key when I see something I'de like to take a screenshot of (and impossible to get good action shots). I'm curious if there is a way within dolphin to map the screenshot command to a button or combination of buttons on the controller?