Hey Josh. At this point sadly HTML isn’t possible within the custom fields, but we’ve had a ton of requests for that so should be releasing code that allows for it in one of our next monthly maintenance releases. What might be easier in the interim would be to change the “Organizer” label to something else: organizers DO allow for HTML in the URL field, so if you needed a URL that seems like it’d be the best workaround until an official solution is available.
Hope that helps and sorry I couldn’t offer up more here. Just know that relief is in sight. If you have any other questions or if I can do anything else, please let me know.