how to give OnPageIndexChanging on multiple gridview ?

Question

i have 3 gridview's

 

gridview1

gridview2

gridview3

 

and all three gridview have paging 

i have made  OnPageIndexChanging of first gridview which is below

protected void OnPageIndexChanging(object sender, GridViewPageEventArgs e)
       {

           GridView1.PageIndex = e.NewPageIndex;
           this.DisplayProject();

       }

 how to add gridview2 and gridview 3 in it