Do you have a supplier who is also an MYOB user? You can link to their MYOB account so that the invoices you receive from them will go straight to your In Tray.
When you receive an invoice from a business that uses MYOB, open the invoice and select Link to MYOB. Now all of your future invoices from that business will be sent to your In Tray.
To stop invoices from particular businesses being sent to your In Tray, just open up another email from that business and select Unlink from MYOB.