Combining same name variables on Parameters in SSRS

Hello all, 

We have a custom field that lists the projectname on an opportunity, new_projectname. Now, many of the opportunities will have the same project name, so at the moment the parameter available variables will look like:

Project A

Project A

Project B

Project A etc.

Is there a way of "reducing" this so any variables with the same name are combined like:

Project A

Project B

Project C

The actual report produces with the selected projects, so the parameter works, just looks a bit messy.

Any help greatly appreciated!