Marking mesh with additional properties

[caperaven]

I have a matrix of meshes and I want to mark what column and row each mesh item is on.
I was thinking about using custom properties but can't seem to figure out how to enable that for meshes.
What is the suggested way to add markup to meshes so that when you interact with it you can read information about that mesh.

I was also thinking that a hashmap where the mesh is the key might work but jaaa, that does feels a bit heavy handed.