My 2 cents:
There are a number of ways to do this currently.
You can setup containers to group nodes any way you want (or multiple ways). I have an infrastructure tree with around 25000 containers that group subsets of 5500 nodes in 100's of different ways.
You could also setup "custom attributes" on the nodes in question and then create a seldom polled dci that queries the custom attribute and have it show up in the "last values" panel on the overview tab of the object.
