Max of two sets

[#1]

If I want to find the maximum value of a column from two states aggregated by a member's ID, should this work?

=Aggr(

    MaxString(

        Aggr(NODISTINCT MinString({[State1}DATE_STRING),MBR_ID) + Aggr(NODISTINCT MinString({[State2}DATE_STRING),MBR_ID)
    )

, MBR_ID)

So if I had this data:

MBR ID          DATE_STRING

1                     20120101

1                     20120102

1                     20120103

And State1 had 20120101 selected and State2 has 20120103 selected, my expression would return 20120103 for member 1.

Thanks!