Hi Simon!
What you describe sounds like exactly the reason for the use of Triggered Emails.
What problem do you encounter while trying to work with this method?
Have you checked this guide regarding the topic?
Note that you could easily distinguish between users using the _ID field.
This field is automatically generated when an item is created (item that represents user’s record in this case). The _ID is a unique field (there will never be two items with the same _ID ) and so you can easily associate between the dynamic page to the user that it belongs to.
Hope it helps!
Doron. 