Transport Rule Condition Block Secondary SMTP for External

Hi all,

Is there a way to limit users to use secondary SMTP addresses to mail external?

For example:

John Smith has manager@contoso.com as his primary SMTP and j.smith@contoso.com as secondary SMTP.

John may only mail external with his primary SMTP manager@contoso.com

I can only block users currently, cause if I add secondary SMTP tobe blocked, it will recognize the User like it does with the Check names button...

thanks in advance