To add a sub-contractor to your Gazelle account:
Step 1: Add this person as a technician to your existing Gazelle Subscription.
Step 2: Have this user set up their own scheduling availability in your company's Gazelle account.
Step 3: Set up a 2-way sync to keep both calendars up to date.
Now all you have to do is schedule an event on their subcontracting Gazelle calendar (inside your company's account) and Gazelle will add the info to their private Gazelle calendar to block off their availability; and when they add something to their private Gazelle calendar it will block off their subcontracting calendar so you know not to schedule them when they are booked with private clients.