In my career in hotels a sizeable portion of staff would be termed back of house team members. The stores men, laundry workers, cleaners, canteen lady and maintenence crew. They may not ever get to be serving the paying customers face to face, but they certainly maintain the operations for those that do.

In other businesses, there may be similar people in the team who look after the warehouse, or transit drivers and others. These people need just as much focus on the paying customer as everyone else in the business, for they form a vital link in the service chain. So ensure they are trained and focused too on the customer.
" If you are not serving a customer, make sure you are are serving someone who is."