How do I combine multiple Subscriptions into one?

The best way to combine more than one Subscription is to disable the Generate separate invoice toggle within each Subscription. 

Steps

To route all invoices across multiple Subscriptions for a Customer, edit the Subscription(s) as follows. 

1. Navigate to Menu > Contracts & Orders > Subscription Contracts.
2. Click Change from the More menu.
3. Scroll down to the Subscription Information section.
4. Toggle Generate Separate Invoice OFF, which will route Invoices across multiple Subscriptions for a Customer and send them to a single Billing Contact.
   Note: When this setting is toggled ON, each Invoice is routed to individual Billing Contacts that may not be the same contact. 

5. Save when finished.