Hey Aaron,
I understand your question now. You want to be able to have an array of attachments in one action result. So you don't have to hard code how many attachments there will be and it automates on the fly.
This should be possible as well.
I would start by heading over to the Invoices screen and take a look at the Button under the Grid for Print > Print Selected.
Look at the Action Set. Give the Generate Report Action an Action Result name and use it on a Send Email Action to test. Following this Action Set you can use it across screens.
Is this what you were trying to accomplish Aaron?
- Mortaza