By nature transactional emails are not groupped like a newsletter campaign so we offer reports by timeline (start / stop date).
But with a simple tweak in your code, you can group messages by type.
For example. Group Order mails by tagging the mails with tag: `order`. Or group Reminder mails by tagging the mails with tag: `reminder`.
For each email tag we calculate detailed reporting + detailed email history search.
Combine this with detailed Email Metadata which you can use to identify the specific email back in your application (the metadata is sent back in the webhook call - link to webook).