Merge dimension in webi

Hi all, I have a webi report which Is created from 7 bex queries, all common dimensions are merged. now we added one more bex query and want to merge common objects from newly added bex query. how can we do this without unmerging the existing merged objects. example:             

Fiscal Month             

fiscal month----------query-1             

fiscal month----------query-2                 ....                 ......             

fiscal month----------query-7.

here fiscal month from query-8 should be merged  to the existing merge dimension(Fiscal Month)

Thanks in advance

santhu