In the resource record put the email address you want for communication with the user in the "Email Address"attribute. Providing there is no rules/filters in your email server the emails to the user from CA PPM should go to that email address. Remember that the notification portlet needs to be setup to send notifications via emails. You have 3 options Alert, Email, SMS. make sure you have Email selected for the appropriate categories.
The above is assuming this is from the end user perspective.
If this is for CA PPM system notifications, the same applies, but I would check with your corporate security if what you want is allowed.