Have separate page number per master page side spread-sheet in Indesign

So I have a document with page spreads, let's say left page has master page A set, and right page has master page B. This for all subsequent pages. A-B, A-B, and so forth.

What I want is to have all pages with Master A to have their own numbering counter like "A-1" "A-2" and so on, same thing for B masters. I've tried with sections but its quite tedious to have to select every single page and specify apply this section and start with number "X", since I can't to find a way to bind a section automatically to a Master Page.

Any proper way of doing this? I'm using Indesign CS6 on windows 7.