Creating a group in a measure

Hi!

I'm creating a matrix containing financial data. My data is from an SSAS source and therefore I can´t create custom columns or use the data och relationship tabs.

Option one is to group five of my accounts together as a group to use as a column. Is there any way I can do that using a measure or IF-statement? I can not filter the accounts on the formatting of the fields tab,

The other option is to filter the same column in two different ways in my report based on if the value is negative or positive.

Green: Net income based on all costumers

Red: Cost based of a group of costumers excluding the others.