Ok, if you want more.
I have a headphone buss, it's outputs are routed to channels 3/4 of my interface and from thereto a headphone distribution amp, via my desk
Now, each buss has a SEND to the headphone buss so you can easily control the relative level of what goes to the phones buss, creating a very rough dedicated mix.
But you must avoid inserting the send on any buss which feeds not to the master, but to another buss, much like my toms buss > drums buss.
If you insert it on both you'll get a doubling up of the volume from the toms because it's being processed twice. This sound really complicated to write but in practice it's extremely intuitive.