How to use local members, when columns expand dynamically according to user options?

HI,

I am working on a report that the user can select the period he wants to plan using the epmselectmember function,  using the epmoverride function the columns of the dimension time can be expanded reading the context that the user selected.

I need a column with the total by account line as last column , how could I use local members that could understand the time expansion and deliver the proper sum of these values?

Any suggestions?

Thanks in advance!