Many famous rabbanim have had the last name מרגליות. A couple that come to mind are ר' ראובן מרגליות and ר' אפרים מרגליות. Are they related? Where could I find genealogical information on such people?
I don't know if they are all related, but you can browse some Margolios trees on geni.com. You will have to give them your email address to become a member, but their not too bothersome and you may be interested in doing your own tree!