How do I get the Owner Manager Email address using JoinFieldValue?

Hello All,

I have a requirement where in I need to send a single email to Opportunity Owner and Opportunity Owner's Manager. How can I get the Owner Manager EMail address using double JoinField Value?

I can do the above by sending 2 emails but i want to send it in one email only.

I have created a workflow and the following has been selected:

From* - Default Email Address

To* - Specific Email Address (Here how can I put the condition here for both Owner's email and Owner's manager email).

Thanks in Advance

Som