I'd like control over which by-reference collection items are visible to my client in the drop down menu when creating a new collection item based on parent category selection.

 Collections: 

 -Collection "Category" multi-references Collection "Types" which by-references back to Category. Collection "Products" uses the collections above to classify an item.

Example:

 -Collection "Types" contains items "Hats, Winter Hats, Mittens, Socks, Winter Socks, T-Shirts, Jeans, Scarfs, Shorts, Warm Leggings, boots.

 -Collection "Category" contains Collection Items "Winter Clothing, Summer Clothing, Hiking,". 

 -Collection "Category" item "Winter Clothing" multi-references Collection "Types" items "Winter Hats, Mittens, Winter Socks, Warm Leggings".

When my client goes to create a new collection item in collection "Products" in this case item "Softy Woven Thermal Socks", they must assign a Category, and then a Type.

 Naturally, the product Category they choose will be Winter Clothing, and the Type will be Winter Sock. 

 The problem is that after selecting the Collection item Winter Clothing to assign a category, the next reference dropdown with Types will display ALL types, not just the types referenced by the Collection Category item  "Winter clothing", so they will see options that if chosen means the product won't display on the correct or any collection page because no logic exists, because Types are only assigned to one parent.

 For instance, choosing Collection "Winter Clothing", and then "Hats" means the item exists no where, except maybe on the "Winter Clothing collection page if i added a list to display "ALL" items with current category.

I'd like a way to control the data displayed in a multi-reference drop down to be conditional upon it's parent reference so clients can't incorrectly categorize products which with 100+ Types, it is very easy to do.

 I should mention this is not an eCommerce store, it's actually a manufacturers product catalog that requires calling in to order