SSRS report using Fetch XML - using the lookup function

I'm creating a SSRS report based on CRM online using fetch xml. Within the report I have several datasets. To link the datasets I'm using the lookup function. I've just discovered that I need to pass two parameters to each dataset instead of one. Can you pass two parameters? I looked at the multilookup function, however I don't think  that will work. An example of my current function is below.

"OpportunityCommitted")

Any help would be appreciated!!!