Visually grouping items in wishlist

I am building a wishlist that allows the user to create groups of items without affecting the master wishlist (i.e. users can add an item to a group through tagging. One item can be on two different groups at the same time).

What is a visual/elegant way for the user to perform this task without multiple popups, overlays, drop-down menus etc like Pinterest?

There is value seeing the groupings in a moodboard fashion to see how the items play together within a group and how groups visually compare to each other. Imagine this is like building clothing outfits.

This is what I have so far: