power of attorney

Hi,

    I own a land. It is at the name of me and my  2 brothers .  Due to some reasons i have to get a power of attorney made at my name in which i have the right to sell the land.  For this i would need my two brothers to sign the papers of power of attorney for me. But as all 3 of us stay in different cities , it is not possible for them to come to my town at the same day . So, is there some way by which i can get the papers signed from them one by one. Means when one of them comes to my town , i get the papers signed from him on that day and when the other brother comes on some other day , he signs the papers then. 

  Please guide.

Thanks.