+-------+-------+
| host  | count |
+-------+-------+
| comp1 |     2 |
+-------+-------+
| comp2 |     3 |
+-------+-------+
| comp3 |     2 |
+-------+-------+

+----+-------+
| id |  host |
+----+-------+
| 1  | comp1 |
+----+-------+
| 2  | comp2 |
+----+-------+
| 3  | comp1 |
+----+-------+
| 4  | comp3 |
+----+-------+
| 5  | comp1 |
+----+-------+
| 6  | comp3 |
+----+-------+

for (int i = 0; i < distinct.Rows.Count; i++)
{
    if (Convert.ToInt32(distinct.Rows[i][1]) < 3)
    {
        foreach (DataRow row in t.Select())
        {
            if (row[1].ToString() == distinct.Rows[i][0].ToString())
            {
                row.Delete();
            }
         }
     }
 }