I don't have any answers, but wanted to confirm that I have this same issue, where I am a co-host for my brother, but I am not always hosting for him, only mainly when he is traveling, so I wanted to be able to turn off or limit the notifications that I get for his property while I'm not working for him. However, I haven't found a way to do this without just completly removing myself as a co-host in the meantime and I told him that he would just need to re-add me when he wanted me to help out with his property again.
If the website doesn't have this functionality yet, I think it would be a good thing to create.
Kristen