Legal Heir Certificate

Dear Sir,I am S.Vijaynath a widower having lost my wife in Jan.2005.She had two brothers and two sisters.All the five are the legal heirs to their father's landed property in suburbs of Chennai.Now we propose to dispose of the land.The prospective buyers are asking me to produce the Succession Cert.or any other alternative to prove that myself and my two children are the survivors to my wife.I enquired and found out that the Succession cert.will have to be applied for in the Appropriate Court and attracts 6% stamp duty on the present value of the property I am entitled for i.e.1/5th share.of land plus newspaper advt.charges,Advocate fees and other misc.expenses which is beyond my means.The MRO of the area said that they have stopped issuing the Family members' Certificate since persons whose spouses are not Govt.employees.My wife was not employed at all.Pl.let me know what is the alternative for me to sign the papers along with other legal heirs to sell the land in Tamil Nadu.My wife passed away in Hyderabad.I am aged 72 years.