To create a rule that groups inventory items you can use the Inventory in cart condition.
This condition triggers when one inventory item is already in a customer's cart. For example, you can use it to discount items for a BOGO, bundle or package.
To use the Inventory in Cart condition in a rule, follow these steps:
1. Navigate to Inventory > Rules in the main menu.
2. Click Create Rule.
3. Give your rule a name that's easy to recognize, and a description of what it will do.
4. Click Add New Condition.
5. Click Inventory already in cart is...
6. Select the inventory items that will trigger the rule.
8. Click Create Rule.