You can add inventory in ecomdash that will not have balances pushed to channels. To exclude these products you will:
1. Navigate to Inventory -> Inventory Management.
2. Make sure the blue auto sync icon next to the SKU# is not visible for products that you want to exclude from inventory control.
3. To turn-off auto sync for a product, make sure the product is checked on the left of the screen and click 'sync actions' and choose 'turn off auto sync'