Yes, to call one another prabhu is all right, but not to become prabhu. To accept others as prabhu, and remain as servant is the idea. But because somebody is calling you prabhu, one should not become a prabhu, and treat others as servants. In other words, everyone should feel himself as servant, and not to think himself prabhu because he is being called prabhu. This will make the relationship congenial.

Srila Prabhupada, From a letter to Himavati Devi Dasi, June 14, 1968