Adsense sharing plugin?

Does this plugin exist?
Here’s the scenario: I have a recipe site which has all the adsense in place, with my own PUB number.

A friend would also like to add her recipes to my site.

I want a plugin that when installed, my friend’s user page will have a place to input her own PUB number, I will also have a place to input my own PUB number, I will then replace the PUB number of the ads which are in place now with some < variable >.
That’s it.
From now own when my friend posts a recipe from her own account, that page will display ads with her own PUB number.
That’s it. Does something like this exist?