One common TV trend is when an actor or actress appears in two different shows that are on at the exact same time. Even more amazing when the two shows are on different networks. There are a ton of examples of this happening including Heather Locklear appearing on TJ Hooker and Dynasty to Armin Shmmerman doing double duty on Buffy and DS9 to more modern examples like Alison Brie appearing om Community and Mad Men at the same time. It can't be easy to be bouncing from studio to studio, not to mention character to character, but it's been done.
Here are five examples of what I mean. And to be clear these aren't actors doing taking a break from their show to do a one time character as a guest star. These actors had multiple appearances on both shows as regulars.
Gail Edwards (Blossom/Full House)
I once read an article where Edwards talked about how crazy it was bouncing between studios. And in this case, networks. Saying she probably had the other shows script with her. On Blossom she played Sharon, who was Six's mother. And of course at the same time she was playing Vicky, Danny's long term love interest.