Hi everyone,
Not sure if there is already a solution provided by zoom or Hubspot in the meantime (that I have not found yet), but I’ve tried solving this one for our Marketing team. Well to specify; we wanted to know all of the webinars that a prospect registered for / attended, without the value being overwritten each time. So I tried setting something up, but I am not sure if it is bullet proof yet, because we should test it with real life data going forward. But here’s what I set up so far:
1. I created a multicheckbox field with all of the webinar names
2. I’ve created a contact workflow with the following enrollment criteria:
“At least one Zoom: Webinar Attendance Event has Webinar ID is equal to any of XXXXXXXX (no spacing)”
with the followup action:
Set property Value: “Append a contact property Webinar Attendance with <Name of the webinar from the checkbox field created in step 1>”
And then normally this would each time check the box of the new webinar they have followed.
Big downside here is of course the fact that it is super manual / labour intensive.
If anyone sees any issues with this, please let me know (would be great to solve them before we use it for live data haha) or maybe it inspires some people to come up with an even better workaround 
Charlieeeee
Rev ops @ C4T