help with @Sumrange across two dimensions

I have an existing formula that looks like this:

Fix(Dim1_member, Dim2_member)
AcctX = @PRIOR(AcctX→noDept→TotalDim1→TotalDim2)

Endfix

What I'd like to do it change the formula so that I don't cross dim on the "Total" members ( "TotalDim1→TotalDim2) but instead I grab the sum of the level 0 members under each. I having trouble formulating that.

Thanks!