For your information Astrology does not approve of any caste system except in the form of Chaturvarnya by the job one does. Those who perform God worship are Brahmins, those who protect us from enemies as Kshatriya etc. Marriage is union of body, mind and soul and when that happens between opposite sexes, it is called marriage. Read my article “Definitions in Astrology” on my blog navagrahastro.blogspot.in