Look! See how good, how pleasant it is for brothers to live in unity! 2) It is like precious ointment on the head, trickling down the beard, trickling down the beard of Aaron, over the fringe of his robes. 3) It is like the dew of Hermon descending on the mountains of Sion, for there the Lord gives his blessing: life forevermore!
Of course it means what you understand it to mean but also [anagogically]:
Brothers that live in unity are the three faculties of the human soul, which if they agree in their knowledge of what is true and good =(Orthodoxy), behold the good. If in addition they agree in acting upon this knowledge (Orthopraxis) behold the pleasant.
Then the Holy Spirit (precious oil) descents on the intellect (head) of such a person and is manifested (runs down) in his words (beard), the words that cut off the passions from the soul of his hearers and plant the virtues (such is the beard of Aaron). And finally comes down in his actions, the fringe of his robe. The end of a robe is the fringe, and the end of all spiritual knowledge (robe) is to act righteously. Also since Aaron represents priesthood, fringe are also the spiritual children of priests (remember what the threads of a priest’s stole symbolize? Btw when the priests put on their stole they recite this very psalm.)
Mountains of Zion are the Saints, those who have been baptized with the dew of Hermon, the grace of the Holy Spirit, which repels the wild beasts (passions and demons) from their heart. (Hermon literally means 'repealing of beasts.' Hermon is also topically the source of the Jordan River, which is a symbol of baptism).
(Source: St. Maximus)