Reminds me of the time, well a long time ago, when I worked at a tech startup during the early 2000 bubble. Talent war was intense. We had recruiters cold calling people's desk to try to lure people away.

At that office, like every desk (many unoccupied) had a normal phone, with an extension #.

In one instance, a recruiter called and it was answered and he/she was told not interested. After that call, every phone on each of the row of desks started ringing one at a time.

After about 3 - 5 such ringings, someone picked up and told them to knock it off.