I have my therapist's office number. When he is out of the office, that number automatically goes to his cell. If he calls from the office, that number shows up on my phone. If he calls from his cell, he blocks it somehow. He's very good about checking his voice mail. Sometimes I just call it to hear his voice--big dork, me.

I can also call the office after hours and push 0 to talk to the answering service in case of an emergency. They would contact him right away.