Report Display Problem

Hi Experts ,

My multi provider is based on 2 cubes . There is a requirement to have selection on field "Z" on report selection screen and display field "Z" which is present historically in one cube (X ) and not in another cube (Y) . Cube Y only contains real-time snapshot data and doesn't contain data historically .Whereas Cube X contains data historically .

If I am using field Z in the multiprovider for displaying in the report then the result is appearing in 2 rows as it is not present in both cubes like below :

Where as I want it to be displayed as below in one single line :

Any pointers how I can achieve this .

Note : Points will be awarded for answers ..

Thanks