How to add 2 dataset of different structure

Ya i've gone through this...and wrote like this...
<pre>MySqlDataAdapter da = new MySqlDataAdapter();
connection = new MySqlConnection();
dbconeector = new DataConnector();
ds11 = new DataSet();
DataSet ds12 = new DataSet();
DataSet ds13 = new DataSet();

//load agent info
ds11.Clear();
connection = dbconeector.connect();
MySqlCommand cmd1 = new MySqlCommand();
cmd1 = connection.CreateCommand();
string qyery1 = "select agents_details.Agent_Employee_Id,agents_details.Agent_Id from agents_details where Agent_Employee_Id=any(select Emp_Id from employee_status where Emp_acc_Stat='OPEN') ";
cmd1.CommandText = qyery1;
da.SelectCommand = cmd1;
MySqlCommandBuilder cb1 = new MySqlCommandBuilder(da);
da.Fill(ds11, "agents_details");
//MessageBox.Show("filled agents id table to dataset");
qyery1 = "select Employee_Id,Emp_Name,Emp_Mname,Emp_Lname from employee_details where Employee_Id=any(select agents_details.Agent_Employee_Id from agents_details where Agent_Employee_Id=any(select Emp_Id from employee_status where Emp_acc_Stat='OPEN') ) ";
cmd1.CommandText = qyery1;
da.SelectCommand = cmd1;
MySqlCommandBuilder cb2 = new MySqlCommandBuilder(da);
da.Fill(ds12, "agents_name");
//MessageBox.Show("filled agents name table to dataset");
dbconeector.close();
dataGridView1.DataSource = ds11.Tables[0];
dataGridView2.DataSource = ds12.Tables[0];


DataTable dt1 = new DataTable("table1");
DataTable dt2 = new DataTable("table2");
dt1 = ds11.Tables["agents_details"];
dt1.PrimaryKey = new DataColumn[] { dt1.Columns["Agent_Id"] };
dt2 = ds12.Tables["agents_name"];
dt2.PrimaryKey = new DataColumn[] { dt2.Columns["Employee_Id"] };
ds13.Tables.Add(dt1);
ds13.Tables.Add(dt2);
DataRelation drel = new DataRelation("EquiJoin", dt2.Columns["Employee_Id"], dt1.Columns["Agent_Employee_Id"]);
ds11.Relations.Add(drel);
DataTable jt = new DataTable("joinedtable");
jt.Columns.Add("Agent_Id", typeof(Int32));
jt.Columns.Add("Agent_Emp_Id", typeof(Int32));
jt.Columns.Add("Emp_Name", typeof(string));
jt.Columns.Add("Emp_Mname", typeof(string));
jt.Columns.Add("Emp_Lname", typeof(string));
ds13.Tables.Add(jt);
foreach (DataRow dr in ds11.Tables["Table1"].Rows)
{
DataRow parent = dr.GetParentRow("EquiJoin");
DataRow current = jt.NewRow();
for (int h = 0; h < ds.Tables["Table1"].Columns.Count; h++)
{
current[h] = dr[h];
jt.Rows.Add(current);
}
}
dataGridView3.DataSource = ds13.Tables["joinedtable"];
}</pre>

it shows error like this...

ds13.Tables.Add(dt1);"Datatable already belongs to another dataset