Icalendar family account

OH 3.4.2 on raspi 4

My wife and me have a separate ical account for ourselves. You can use them pretty well with OH and even the command properties do their job. For dates concerning both of us, there is a family account. But this account does not support an official key (just showing the opposites e-mail account), which prevents the use in OH. How can I link this account to OH.
Best regards.