When manually sending emails via the native fuctionality on transactions, is there a way to set a different From Email Address depending on the subsidiary?

I tried with a workflow and send email button

Our email message though is custom. Is there a way to source the email message from a custom field?

in a workflow you can choose the email template in the settings for the send email action

We actually don't have a template because the email message is almost always custom or cannot be standardized.

If you are selecting "new - email" or "actions - email" and then setting up the email to send I believe the answer is no since it's coming from the user assigned email. The only exception I know of is invoices as there is an invoice email address in the subsidiary settings manager, but, I don't know if that works for the above methods of sending or just the automated version (send via email - save).

Got it. I will try that for invoices. Thank you, Simon.