Grouping by property According to a condition

Hi Gurus,

Well, imagine there is 2 user-defined property of a dimension as "A" and "B".

And in a report, i just wanna group the members of this dimension according to a simple condition.

suppose that the user select company code "800" then dimension should be groupped by property "A".

and if the company code "700" is selected then it should be groupped by property "B".

is there any chance to do it?

Thanks in advance.