If you are submitting entries for more than one newspaper:
You will need a separate user account for each newspaper that will be submitting entries. And EACH account does need a UNIQUE email address.
If you just don't have enough email addresses to make things work: Hack: If you need to make more than one account and it is just not possible to find enough unique email addresses, don't worry too much about it - you can type in a dummy email address just to get past the robot - something like (newspapername)@example.com. This will mean that you won't get confirmations as you post your entries, and you can't reset your password online, but you can always email Julie Anne to help out with that if that's the case.
Sorry this is a bit of a bodge :P