A group is just a name for a bunch of inventory items that you sell together as a group.

Create a new item, of the type Group, name it. In the group screen there is a place for listing the items that make up the group, select what items are in the group. Then decide whether to print all items on the invoice or just print the group title. If you select do not print all items, on the screen in QB you will see all the items, select print preview to prove to yourself that when printed you will not see all the items.

When a group is listed on the screen, you can click in the description block of one of the group items, use the main menu Edit>insert line or Edit>delete line to do just that. Then you can add in or delete an item.

You cannot get sales reports by group in QB, but if you assign a class to the group, then you can get class reports that will show sales.

Groups add up the total of the sales prices of the item in the group, if you want the sales price to be less that total of the parts, then add in a sub-total item followed by a discount item in the group list.