Sorry, but each eBay account has just one email address, and each email address can only be used on one eBay account.
Many sellers prefer to keep their buying and selling on separate accounts anyway, so that buyers can't see how much you (the seller) paid for the item that they (the buyer) just purchased from you. You can have multiple eBay accounts attached to your PayPal Business Account, so you would be able to get that part of what you need done even if you have to use different eBay accounts.
eBay does offer some Listing Management tools, which might be able to give you what you want. You will have to check out their features and see what they have to offer. I have not used these myself, so I'm sorry, but I can't give you a personal recommendation.
You mgiht want to check into:
- Selling Manager Pro
- Blackthorne
- Blackthorne Pro
You can get more information here. They are listed under "All in one solutions":
http://pages.ebay.ca/sellerinformation/sellingresources/sellingtools.html