I'm not sure about omaconfig but other places that you can put multiple email address would expect them like this:
ALERTEMAIL=("REC1@EMAIL1" "REC2@EMAIL2" "REC3@EMAIL3");
with the individual email addresses quoted and delimited by a space surrounded by parentheses.
sorry...just looked it up:
To specify more than one address, enclose each address in single quotation marks, place a blank space between each address, and enclose the list in parentheses. For example: "('Bill@mycompany.com' 'Susan@mycompany.com')"