lists within lists

hello everyone!

sorry if i refer to things using the wrong terms...

if I have a list that  is subdivided in groups with equal number of items (group "0", group "1", group "2", etc...), how can I relate items in "0" to items in "0", items in "1" to items in "1", and so on?

to be more graphic, all the items in the list are points and I wanna run a Pline through items "0", another one through items "1", and so on...

I can use the list item component, but that will only allow me to isolate one item group at a time (unless I add an expression to it?)...

any help will be appreciated.

cheers!