mail account with 2 passwords

I have this requirement. Client uses exchange server. Two people will have the same email account with different passwords.

To open the mail account, both of them together have to provide the password in 2 steps. Can 2 static passwords can be supported in this scenario or it has to be like 2 step validation with one static password and one dynamic code received through a phone. How can the 2 static passwords can be implemented.

Thanks

ramakrishna