You do not need to start a new inventory.
You will create an item group called "Living Room Sectional" which consists off 5 Boxes/SKUS. The customer will only see the sectional but your warehouse workers will see the 5 skus. QuickBooks Support Can help you set this up.
Example:
Item: Living Room Sectional
1 x SKU 62452 Corner
1 x SKU 62500 Left recliner
1 x SKU 62550 Right Recliner
2 x SKU 00020 Armless Chair
