you will need to use the implode function like my previous examples.
I tried swapping $_POST with implode like you've mentioned, but get syntax errors if I don't include $_ before it.
where are you putting this code?
what exactly is the code you are using?
if you are getting syntax errors, it;s because you are not implementing the code correctly, I wont be able to what the issue is without seeing the code you are using.
also, what version of universal email?