Unethical registration of ancestral property

Dear Lawyer My grand parents who had expired recently held an ancestral property in the district of West Godavari district Andhra Pradesh. They had 4 sons and 5 daughters. Now, these 4 sons together conspired to usurp the property without daughter's consent. They had been threatening their sisters to sign on the white and registration papers. They were even successful to force the youngest daughter to sign against her wish. Now, they are planning on visiting registrar office to register the property as well. The daughters had telephoned the registrar and informed him of their situation and their inability to visit the locality. But the registrar mentioned he couldn't hold the registration and will continue providing documents to the 4 sons. please advise on following questions on this premise. Questions: 1) What should the female descendants do at this juncture? 2) Why can't the registrar halt/terminate the registration? 3) will the property become their's if they register it? if no, how long the daughter's have to reverse the registration through court? if yes, Is this lawful and legal on the son's part to do so? Please advise your suggestions Thanks