I solved this one pretty quickly once I posted the question up, but I thought I would share the solution since I couldn't find it on here.
What you need to do is subscribe to a smart list.
For my particular situation I created a smart list (local asset) within the event program and called it "Registered for event".
I then clicked on the smart list tab for the smart list and added the following:
After setting up the smart list to pull in the everyone that had registered I simply right clicked on it in the left hand menu and selected "New Smart List Subscription".
From there I was able to edit the settings such as how often the update should be sent and to who.
This article in the Marketo documents will also help you Subscribe to a Smart List - Marketo Docs - Product Docs