Scripting Newbie Help

If I have a group of primitives representing 2 objects, and those objects are linked together into one big object, then how, in script, can I move just 1 prim or 1 object a certain amount?

for example, say I have a measuring tape roll with a tape object linked to it. When the script runs, I want the tape to extend (stretch) out of the roll. The tape itself could be made of 2 prims and the roller made of 3 or 4. If this is all linked together and the script is on the base object of the roller, how in that script do I tell it to stretch or reposition the 'tape' object?

Assuming the tape is made of 2 prims, would I have to put the stretch script on both prims of the tape, so that when the trigger hits, the script acts and moves both pieces?

Let me know how this works please =)

Would the section at the bottom of this page, regarding Child Objects, apply to what you're doing?

http://www.badgeometry.com/wiki/llSetPos