RNA PoN

Hello,
We want to create an RNA PoN in Firecloud. We already have the workspace setup. Now we need to identify the RNA normal samples in TCGA data sets which are already in Firecloud and other external datasets and import only those samples into our workspace. Once we have our dataset of RNA normal samples, we would need to modify the variant calling pipeline for RNA. What would be the best way to do that? We would appreciate your help.