A] If possible go in Rajasthan or Goa and buy some small agricultural land where you dont need to be farmer to buy Agr. land by existing laws. Get your name on papers show some crop to ensure you are doing agricultural activities.After that buy agricultural land in Gujrat.Than produce those certified copies of land in other state(i.e.Rajasthan or Goa) in Gujrat Revenue offices as evidence of being farmer to enroll your name in Gujrat
B] If your brother in law is farmer your sister is naturally farmer ,you may finance her on paper to buy Agricultural land in (Gujrat) her name.Then get registered Power of Attoerney in name of your wife (or any person whom you trust) which should contain all powers to deal with Revenue authorities alonwith right to transfer the said land.After that show yourself as person tilting that land and enroll your name in that land as tilter (you are now farmer). After a period of time buy half portion of the same land in your name ( YOU have already paid)
C] Apply to the collector specifying permission to buy Agricultural land and than keep following it which only god knows when you would get it. Atleast this is the state in Maharashtra .Get good lawyer and confirm the above modus operandi.