How to… separate busses in new ways

We often group signals of the same type for ‘gluing’ compression. Often, this means summing drum and percussion tracks to one bus, keys and chords to another, and perhaps vocals to yet another. But try looking at things differently: how about grouping channels based on their frequency characteristics? Setting up busses for low, mid and high frequency instruments would lead one grouping channel for, say, kick, bass and sub tracks, which are compressed differently from the snare, piano and vocal tracks, which in turn receive different dynamic tweaks than hi-hat, acoustic guitar and percussion tracks.