How to add two datasets inside a same tablix?

Hi Everyone,

I want to create a report as using project server datas with two datasets in the same tablix.my report has three grouping by Months,Resources, and Resource Role.my dataset has resource name parameter.when i selected a few resource as filter,LookupSet function gives me an array.But it is taking first value of array for each resource.Actually it must get related value for resource in the array.