Put up a "shed".
If your current system supports only the amount of bedrooms you already have you may have an issue. Turn one of them into an "office". The alternative beyond that is expanding your system.
I heard a while ago that Gilford was shying away from allowing bunk houses. I am not sure if that ever came to fruition or not, or if other towns are following suit.
My neighbor built her house a 2 bedroom with 1 office so that she could have a 1 bedroom bunk house at some point.