You probably already know that you can group items in your sales orders and assign custom group pricing. If not, and you'd like to learn more, see Group products into item groups.
If you are already taking advantage of item groups, did you know that Inform provides handy shortcuts, as well?
With any line item selected, press Ctrl + G.
In the Add to Group box, select the group to which you want to add this line item, or type a new group name to create the group and add the product to it in one step.
Item Group column
You can also group items directly from the Line Items grid. In the Sales Order, on the Details tab, click the Field Chooser and select the Items Groups check box.
From the new Item Group column that appears, you can assign each product to a new or existing group.