I open iterm2, then click on Shell / split vertically, and then it prompts me for a profile, repeat until I have the 4 sessions I need, then delete the default 1 I don't need.
Then I click on Shell / broadcast input to all tabs
HOWEVER, I'm looking for a better solution similar to what I think you want.
I would like a profile that opens 4 ssh sessions (same username, just different servers) in different tabs, and sets it to broadcast input.
I havent figured it out either.