How to use a values from two data collection in one crosstab / table

[erwink]

Hi cognos gurus

Running with DRM

I have a collection UserID, ProjectID, MonthID, EffectiveH with xxxID connected each to a Dimension.
The value EffectiveH is spend hours per employee per month on a given project
On the other hand i have a Collection with MonthID, LocationID, PossibleH with xxxID connected each to a Dimension
The value PossibleH  is total monthly working hours per location
LocationID and EmployeeID are part of the same hierarchy

What I'm asked to deliver is a crosstab per Month (best) or Table for one month filtered in one project

User , EffectiveH , PossibleH  , SomeCalcWithH

How can I bring those two collection together. I tried with join and others but no way!? Or has someone another idea.
I have access to the whole tool chain: DataManager, FrameworkManager and ReportStudio

Thank you
erwin