Can I set my form to show lvl0 cost centres of the member I selected in my action menu

Summary:

I'd like to create a summary form where users can right click a parent cost centre and then go to an input form with only lvl 0 cost centres of that parent.

Content (required):

I'm trying to build an ASO planning cube that allows users to see summary level data and then select a small part of the cost centre area where they may need to make changes. The ASO is capable of opening all the cost centres, but turns into a bit of a monster with thousands of rows and takes a performance hit opening. I can set context menus for individual cost centres, but when I have a report form with upper level members, how can I get the next form to use that for context and show the children