You should be able to disable the email option in Maintain Customers > Document Transmittal.  This brings up the record for the Primary Contact.  You will need to uncheck email for all the transactions in the Transaction drop down.  For other contacts associated to the Customer record, select Other Contacts and deselect the transactions to send emails to.

Thanks LouDavis. I did as you instructed however once I uncheck the E-mail option for the primary contact it also unchecks and disables the "Include Other Contacts" checkbox. The other contact that I setup to receive Sales Orders does not work even though it is still checked to receive Sales Orders.

Hmmm...  That's an issue that maybe Sage will correct in the future..  Ok without doing a customization as you would need source code, a possible solution is to modify the primary contact to be one of the contacts that needs to receive the email and take your current primary contact and create an "Other Contact" record for them.  That should allow you to work around the limitation and still keep the original primary contact a contact associated to the customer.   

Thank for the suggestion but then the new primary contact would receive all emails.I guess I'll just have to chalk it up as a design flaw and write my own email procedures.

Thank for the suggestion but then the new primary contact would receive all emails.I guess I'll just have to chalk it up as a design flaw and write my own email procedures.