Kalopani,
I dont have any specific objective in knowing this info. I was just curious as something reminded me of historical events involving person of this surname. Hindu dharma is too complex i guess. It wont allow a marriage between people of same Gotra, but i just knew that basnet-basnyat (if they are different) , thapa-thapa, karki-karki or poudel-poudyal are allowed to get married. I think, people have defined these hindu-marriage-codes according to their convenience. I find these thing interesting, just dont have time to search and read these caste/ethnic related history of Nepal.