Fill combobox with multiple datasets from the same database column at the same time

I have a combobox that is filled from a database conditionally by checking off one of 10 checkboxes. Each of the 10 checkboxes contains the code below, which selects a portion of column based on a value in column2.

private void Check1_CheckedChanged(object sender, EventArgs e)

    {
        if (Check1.CheckState == CheckState.Checked)
        {
            // SQL Server connection
            SqlConnection conn = new SqlConnection(@"Server = Server; Database = DB; Integrated Security = True");
            DataSet ds = new DataSet();
            try
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand("SELECT [Column1] FROM [DB].[dbo].[Table1] WHERE [Column2] = 50", conn);
                SqlDataAdapter da = new SqlDataAdapter();
                da.SelectCommand = cmd;
                da.Fill(ds);
                combo1.DisplayMember = "Column1";
                combo1.ValueMember = "ID";
                combo1.DataSource = ds.Tables[0];
            }
            catch (Exception ex)
            {
                //Exception Message
            }
            finally
            {
                conn.Close();
                conn.Dispose();
            }
        }

        if (Check1.CheckState == CheckState.Unchecked)
        {
            combo1.DataSource = null;
        }

Therefore, it is rather trivial to fill the combobox with each separate condition. What I want to do that I'm not sure of the approach, however, is that when more than one checkbox is checked, the combobox will display the data from every checked checkbox at once (all this data will be from the same column). Moreover, when a single checkbox is then unchecked, I only want it to remove its own dataset from the combobox and not everything.

Is this possible?