Owl Video supports individual, couple, and family sessions. For couples or families, it is important that you link the accounts, and have all relevant Attendees listed on the session you create (see guide here).
When multiple Attendees are connected on one session, and it is a Video session, each client is able to access their Client Portal and connect individually. Remember to ensure each Attendee is set up with a Client Portal account (guide here), just as you would with an individual session. You would then run your session as usual, but with more than one client.
At this time, the emails do have to be unique for each Client Portal log in. If the family only has one email address used for all members, there is a potential workaround if the family is using certain email systems, such as a Gmail or Outlook email account. You can add a "+" sign to the end to use an email address that looks different, but goes to the same inbox.
For example, if their current email address is hello@gmail.com, they can use the email hello+person1@gmail.com, and still receive the emails as they normally would. So the first family member can continue with the usual address, while the second family member signs in using slightly varied versions of the email (which still connects to the same inbox).