Have the door closed during certain hours (slack has a dnd mode, which can be overridden if it is important) then people will learn to contact you during those

Have the door closed during certain hours (slack has a dnd mode, which can be overridden if it is important) then people will learn to contact you during those times, especially if you down prioritise those who accept the system. You are going to catch some slack, offset that by producing more/better than anyone.