BEx query - aging summarized at the GL account level

Hello,

I am trying to create a BEx query that ages at the GL account level, like the example below:

Company          GL Account          Net          Net Over 90 Days

2010                    2190090          $100               $50

2010                    2216035          ($200)             ($100)

2090                    2190090          $1000              $800

I've built aging reports that list out the individual records within the GL accounts and individually age those records, but I haven't built one summarized at the GL Account level.  This report is also in FS-CD, not FI - in case that matters, but I don't think that matters too much, it's the same concept (we have Posting Date to use for the Current Calendar Day SAP Exit).

I've tried to make a restricted key figure for the Net Over 90 Days column, but that is not working.  I am wondering if it needs to be a formula instead?  Or maybe a restricted key figure used in a formula?

Thank you for your help.

Angela