Unable to open e-mail account

I want to be able to open an e-mail account from Exchange 2000 on a different login from which it was created for.

E.G. The login name is Bob, and has his Outlook 2000 client is configured to Bob’s Exchange email account. But I also want to create another Outlook 2000 profile on Bob’s account and add John’s email account to open on Bob’s login.

I assume that the mailbox rights need changing on John’s email account in AD, Exchange Advance, Mailbox Rights (to allow Bob to open his mailbox?)