Can a staunch srivaishnavite have marital alliances with other sect brahmins?

Answer : In those Vedic Era, there were no sects or sub-sects but all known as Brahmins irrespective of their following. According to researchers and some Vedic Texts, these splinters and splits are only of about 1500 years old . No, the Gothra is different in persception. Same Gothra is known as Sahothra – meaning brother-hood. Irrespective of faith and sect, it is strongly advised not to marry of same gothra person inter-alia. Whether any sect, sub-sect of Brahmin family, the Gothra root is one and the same. Hence never to marry a person of the same Gothram. Remedy and precautions are unwaranted. If the Brahminism is to survive, it is for the Brahmins themselves to realize the Brahman and act accordingly to His/Her faith but without diluting the Identity of self. That is the essence of Sanathana Dharma. Unity in diversity.