Deeply meditating disciples should concentrate on their guru - Yogananda.

Deeply meditating disciples should concentrate on their guru…It is sufficient for a disciple to think strongly of his guru before meditation. He will then find his meditation on God to be reinforced by God's power flowing through the direct channel of the guru. During meditation, the spiritual vibration of a great master silently works on lesser yogis who may be meditating with him, or who are in tune with him, regardless of distance.

Paramahansa Yogananda