Photo backdrop

I'm not sure if this is really possible..but here goes ^^

I want to make a backdrop area for photographs, with prim plants and such able to be placed depending on the person's needs. I could make it possible for everyone to move the plants via the object paramaters, but then someone might get bored and move them 4 million meters away from where it should be...

Is it possible to use LSL to allow anyone to move the plants and props, but limit how far they can move them from the original point? ANd, even more, is it possible to have someone pay a single box, say 10 L$ for the privilage to move the props, not just the box...?

Simplistic approach:
You could script the props to occasionally check their position and move back to a pre-specified point if outside a pre-specified region.

You can allow access thru a group only and require L$10 for group membership.

Eleborate approach:
1. Avatar X pays the payment box
2. Payment box tells props that Avatar X has permissions to move them around
3. Avatar X clicks Prop N to move
4. Prop N requests control permissions from Avatar X
5. Avatar X uses cursor keys to move the prop in a horizontal plane, limited to a pre-defined region.