Satapatha brAhmaNa is one of the most important brAhmaNas that describe sacrifices. It gives a general principle which answers your question.
And when he offers that offering, he pours out (the ghee) towards that same sap of the sacrifice (in the water) and draws it to him. And, indeed, he pleases those deities to whom he offers that ...
Who are gratified when the sacrifices are performed by the demigods?
Themselves, and also Brahman.
The Madhu-Vidya is a meditation in the Upanishads where you meditate on the Devas. The question is, can the Devas meditate on themselves?
Kind of. They are actually meditating on Brahman within themselves:
Sri Bhashya of Ramanujacharya, Vedanta Sutras -