Hello

I import contours rom EPS files. And after - I need to working with each contour separately
I hoped Group node will help me. But no

I created Group node for each contour and selected each contour separately for each node.
I dont know why - but EACH Group node drawing full geometry, not only this concrete contour.
Why?

How I can working with these contours separately?

Group nodes only create groups, they don't split them from one another. You can use these groups as a selection in a lot of other nodes if you don't want others to be affected, or use split nodes if you want to isolate them.