Because i'm feeling generous, and because you've just mentioned that you only need one POP3 separate account, and the rest are basically a distribution list, how's about the following:
1) You set your MX records to my spam server
2) I spam filter your entire domain (I normally charge £15 per domain per month to spam filter) and deliver to my Exchange service
3) I set up an Exchange distribution list for your other 6 addresses to feed into the first address (assuming all the other aliases are on the same domain)
4) I forward on the one account you need separate to a POP3 mailbox of your choice
...all for £10/mo, payable via standing order.
send me a PM about it all anyway.
