Disable facetime from router due to bandwitdh issues?

Ever since my sister has been "facetimeing" with her friends I lag out of every single online game. I'll "red-bar" over and over. I noticed it happens sometimes when she streams youtube vids but it's not as bad. How do I disable facetime through my router? I use Verizon if that matter's or not. I appreciate all and any advice and suggestions.