You can use attributes to group items within your Parties.
Here's an example Party grouped by "Collection":
You'll see that there's a section for items with Collection=Disney as well as an Other section for items that don't have any Collection attribute. If there were items in this Party with other values for Collection then you'd see a separate section for each of those as well.
You can set the grouping attribute on the Party create/update form:
This should help your customers find exactly what they're looking for with less fuss, and less fuss means more sales!