There is a hadith where the Prophet (saw) told one of the Sahaba to choose a wife from a tribe different to his, and then to choose for his son a wife from a third tribe, and to seek for his second son a girl from yet another tribe.
Islam does not encourage marriage within a caste or family, but merely permits it.
btw, since you are really concerned, hubby comes from a rajput family (but does not consider himself rajput), I don't.