(google)maps raster overlay for donations

hi there,

i want to create a kind of overlay over certain landmarks of google maps (forests and grasslands to be specific). the overlay represents an area than can be donated to and should be divided in smaller rectangle like areas where one rectangle represents 1m² of land. someone can click on one or more rectangles and subscribe to it with a montly or yearly payment plan. he now is a donator and can (if he likes) be publicly visible. so the selected rectangles on the map are now unavailable but display who the donator is if he desires.
I’ve made a picture to hopefully explains it more.
thank you!