cost center hierarchy

SDN Guys,

I have a peculiar situation in which I have 4 hierarchies for cost center and I want to create a variable for cost center so that I can pick up one of the hierarchies when I execute the query. How can I create that variable ?

When I select one of the heirarchy from the variable above I need one more variable so that I can select the node for the selected hierarchy.

kinda urgent, Thanks