You can use /scon -at1 which means: Send the command to all server windows which are connected.

Code:
alias myAlias {
  scon -at1 if ($me ison #chan1) && (BOT ison #chan1) { do this }
}

However I recommend to use "Network name" and just check that in the that condition then use an alias and call its name in here instead of writing the code...
Code:
alias myAlias {
  scon -at1 $iif($network == MyNetwork,CallSomeAlias)
}


Btw, like the what '5618' just told you can make a loop through the $scon() and make that network active then execute your command.

Nothing...