I have an EDMS application already installed in my Redhat linux server and it has been working as required. This application also has workflow engine inbuilt and send an email alert when ever there's a work item in your worklist. The mail alert sent by the application bounces my mail server first, then from there goes to the right recipient

Right now, i have created some other domain on this application to manage other companies where hosting from our site. But i need to configure it to send an email alert to them as well which has not been working for me hitherto.

Please assist on how i can do this? I know linux is more flexible to manipulate.

Thank you chaps