Invoice and Estimate email#4591

I need to send estimates, and delivery notes to the Maintenance Clerk only and the invoices to the Accounts Department and the Maintenance Clerk, but the system only allows one format of customer email line. maybe have an customer email loadsheet and a tag where the required documents can be tagged. So, if I have email A as the Clerk and B as accounts maybe C,D, and E eails but your system should allow me to check the documents i want to set as default emails for those documents. but also i don’t want to be limited i still want to add an email maybe even email D just before the email is sent even if email D isnt an default email for that specific document