Is it possible to do an After Rollup of an After Rollup in 8.4?

[squish88]

My issue in a nutshell is this I've got 3 different cost categories from 3 different data sources (from different "database" types as well...Oracle, SQL server, Excel).  The total of which needs to rollup their related sites, the averages of those totals will then rollup to accounts, regions, territories, etc.  What the users want, is an average of those totals at the higher levels (regions, territories, etc).
     My problem is, in order to total these 3 costs from 3 different data sources, I have to bring them in to the cube as measures and total them with a calculated measure to get the total cost.  Only way to do that is for the calculated measure to be an after rollup.  That gets me the totals.  Then I need to average those totals out by accounts, regions, territories, etc. but can't do that because it would need to be an after rollup calculation of an after rollup calculation.  Any ideas for a way around this?