2 iphones, 1 appleid and both phones ring when I'm being called

I have 2 iphones with seperate numbers. 1 for work and 1 for private use. I want to keep these 2 communities seperated. When someone calls me on 1 number, both phones start ringing. The number which is being called often recognizes the caller ID and start ringing 1st but with the second ring both phones are ringing. How do I stop this?