Grouping members together

One of the weaknesses of Analysis Services, in my opinion, is support for creating custom groupings of members. I reckon that 90% of all calculated members on non-measures dimensions must be doing just this, ie just doing an AGGREGATE or SUM over a set of members, and yes calculated members will return the right values but my complaint is something else. It’s that you then have no idea what members were aggregated together inside this calculated member, and that functions like VISUALTOTALS, NONEMPTYCROSSJOIN etc that you would like to be ‘group aware’ of course aren’t. Some examples needed, I think…

Consider the following query on Foodmart 2000:

WITH MEMBER [Customers].[All Customers].[USA].DEMO AS ‘AGGREGATE({[Customers].[All Customers].[USA].[CA], [Customers].[All Customers].[USA].[OR]})’
SELECT MEASURES.MEMBERS ON 0,
{[Customers].[All Customers].[USA].CHILDREN, [Customers].[All Customers].[USA].DEMO} ON 1
FROM SALES

Wouldn’t it be nice, then if VISUALTOTALS ‘knew’ what was in the set and this query

WITH MEMBER [Customers].[All Customers].[USA].DEMO AS ‘AGGREGATE({[Customers].[All Customers].[USA].[CA], [Customers].[All Customers].[USA].[OR]})’
SELECT MEASURES.MEMBERS ON 0,
VISUALTOTALS({[Customers].[All Customers].[USA],{[Customers].[All Customers].[USA].[CA], [Customers].[All Customers].[USA].[OR]} },  "* DEMO")
ON 1
FROM SALES

returned the same results as this query?

WITH MEMBER [Customers].[All Customers].[USA].DEMO AS ‘AGGREGATE({[Customers].[All Customers].[USA].[CA], [Customers].[All Customers].[USA].[OR]})’
SELECT MEASURES.MEMBERS ON 0,
VISUALTOTALS({[Customers].[All Customers].[USA],[Customers].[All Customers].[USA].DEMO },  "* DEMO")
ON 1
FROM SALES  

And that when you did a NONEMPTYCROSSJOIN against your calculated member, it would return the same results as when you did a NONEMPTYCROSSJOIN against the set that was aggregated in the calculated member? And perhaps also that you could drill down from the calculated member to see the members inside it?

Of course this isn’t possible at the moment, because a calculated member could contain any sort of calculation, so AS simply can’t make any assumptions. But if there was a special kind of group calculated member, which simply took a set of members as its definition and which always returned an AGGREGATE of that set, surely AS could make these assumptions?

Just a thought…