Hi Matrix,
First of all, SharePoint list forms don't support repeating sections. You could create a full-fledged InfoPath form that edits your SharePoint list but I'm not sure that's what you are going for.
So, I need more details on your scenario and this notion of "other section". What's that refer to?
Can you explain your form from a user and not from what you think the implementation should be?
Might be you are approaching the problem in a weird way...