Upstream tools end in a Summarize Tool that has set of records with the following fields: EmailAddress, AttachmentUNCPath. So you get a bunch of recipients with various attachments. Each recipient can have different attachments, and this will change each time it's run. In other words, it's fully dynamic.
If the same recipient has multiple attachments, then it would be nice to group the recipient and just separate the attachments with a semi-colon (or whatever) in the same field. Essentially creating one record per recipient, and therefore one email per recipient, and having the Email Tool attach each file. In other words, email@example.com gets one email with 5 attachments. And next week maybe only 3 attachments, and so on.
Currently the only way I see to accomplish this is with a batch macro.
Would be infinitely more convenient to just have the Email Tool by default accept multiple attachments in a field as long as they are separated by a semi-colon, much like occurs in the "to" field.