Property among brothers left undivided

Grandparents had passed away without partitioning the property among their 3 sons. Property(site) stood in grand parent's name.Eldest son constructed a RCC building in central part of the site without caring for Vastu doctrines and he had passed away leaving behind 3 sons and a daughter, who are all married now.Grand parents have 3 daughters,all married before 1984.The other 2 sons of the grand parents have 2 daughters, 2 sons.Now the dispute of partitioning among the sons is unsettling .Please clarify how to partition among sons and the other stake holders.The sons of eldest son have built a house in the vacant site(1 part) without the notice of other 2 sons of grandparents and wanted to rent it out now, and this is another tricky issue.