There are a few things to consider when deciding to add another business to an existing Cliniko account.
Firstly, as far as the account goes, the owner owns all data - there’s not a way to say that one owner owns part of an account (though you can have multiple owners on a single account!). A lot of data (like patients) also aren’t assigned to a business/practitioner. So there may not be a straight forward way to decide who owns what - particularly if there are patients who haven’t had an appointment within Cliniko.
Now we offer services to help transfer data from one account to another, so if you do have a practitioner that wants to be added to the account, but hopes to take their data out of the account in the future, they could. You can read more about that process here: Transfer from Cliniko to Cliniko
When doing that transfer you can filter data by practitioner or business. We filter the patients by those that have actually seen a practitioner or had an appointment at the business chosen.
On the other side, you can run multiple accounts for each practitioner/business. Admin would be able to log into all accounts at the same time to schedule appropriately. However if you go that route those accounts won’t talk to one another at all - so if you have patients seeing multiple people you may have multiple records.
Hopefully this information helps in making a decision on what would be best for your situation!