Here is how to connect each web-conferencing service per email. You have 4 calendars each linked to FreeBusy and you want to connect conferencing services for each of the linked email addresses, here is how to go about it.
It is possible for you to achieve this, all you have to do is:
First, Log out of the web conferencing platform you wish to integrate from all current logged-in emails, then once you log out, you can then go on FreeBusy.
Next, go FreeBusy in the calendar and integration section, choose the conferencing service (zoom, teams, google meet, etc.), you prefer, and try to link web-conferencing service,
Afterward, you would be prompted to log in to the service in the authorization popup.
Log in with your preferred email account to the conferencing service.
Lastly, grant authorization and you can see your conferencing service linked to FreeBusy in multiple email addresses.
Here is how it would appear with different emails while creating/ediditing an event template
Kindly note: This may require you to login again or relink your calendars. Link those calendars again from. https://freebusy.io/app/integrations.