I'll refer you to Sports Night.

https://youtu.be/qYWBBFJKlPM

https://youtu.be/NMcLXG6PXto

Also from Andrew Sorkin...

    • Joshua Malina: Jeremy Goodwin (Sports Night) / Will Bailey (The West Wing)
    • Janel Moloney: Monica (Sports Night) / Donna Moss (The West Wing)
    • Felicity Huffman: Dana Whitaker (Sports Night) / Ann Stark (The West Wing)
    • Clark Gregg: Calvin Trager (Sports Night) / Mike Casper (The West Wing)
    • Timothy Busfield: Director (Sports Night) / Danny Concannon (The West Wing)

What about ER? I thought that Tommy Schlamme was a big part of the creation of the walk and talk?