WP Supersized + Nextgen Gallery

Hi, i’m trying to put different background for my pages, I want to put different images depending on witch page I’m but I don’t know how to do it.

I’m using the pluguins Nextgen Gallery and WP Supersized, I I have no idea how to work with them together….

When I put one gallery as background it becomes the background of all my pages, how can I put different galleries for each one?

Thank you.