Send bulk email with output medium 5 on invoices

I have configured output medium 5 for standard invoicing. Customer has requested that they receive only one email per billing containing all invoices generated rather than one email for each invoice. Does anyone have a solution for managing this output to send only one email for all invoices rather than one email per invoice? Invoice list does not contain the detail needed unless yuo have a recommendation using this method that will provide the ncessary detail data.

Thanks in advance for your help,

Lynn Gordy