1. Senior godbrothers may be treated as guru

    One who teaches can be treated as Spiritual Master. It is not that after we become initiated we become perfect. No. It requires teaching. So if we take instruction from them, all senior godbrothers may be treated as guru, there is no harm. Actually, you have only one Spiritual Master, who initiates you, just as you have only one father. But every Vaisnava should be treated as prabhu, master, higher than me, and in this sense, if I learn from him, he may be regarded as guru. It is not that I disobey my real Spiritual Master and call someone else as Spiritual Master. That is wrong. It is only that I can call Spiritual Master someone who is teaching me purely what my initiating Spiritual Master has taught.

    (From Srila Prabhupada's letter to: Sri Galim  —  Delhi 20 November, 1971)