This will depend on different factors, including how you want your business set up, what information you want to share and what information you want to remain private. You have the option to either:
a) set up a new group; or
b) add the practitioner to your group and restrict their access via clinic restrictions.
Setting up a new group
By setting up a new group, each group remains independent and cannot see each other's information.
See Can I use a single Halaxy account for my private practice as well as a group practice? for more information on how to set this up and switch between groups.
Add the practitioner to your group
Invite the practitioner to join your group in Halaxy. When you set up their access, select Clinic Restriction so that they only see the clinics they have been assigned to.
Next, go to the Locations page, where you can set up the one location which acts as an independent business (you can input the ABN). Each practitioner associated with that location can be added with their own ABN.
NOTE: there are some details that are shared across the group, including reminders, templates and payment settings.