Check another table for record before delete - asp

Hi,
I have a table called 'age group'. with 2 fields:
agegroup_id
agegroup_desc

I have another table called 'client' with many fields, one of which is called:
agegroup_id
The field 'agegroup_id' is a combo box which options are lookedup from the 'age group' table.

Now what I want to do is to prevent the Administrator from deleting records from the 'age group' table if the record ('agegroup_id' value) has been used in the 'client' table.

I figure I need to check the 'client' table existing records to see if the particular 'agegroup_id' has been selected but I am not sure how to incorporate this with the current Delete function (seen below).

Please could someone help me?  Thank you.

'-------------------------------------------------------------------------------
' Function DeleteData
' - Delete Records based on input sql criteria sqlKey

Function DeleteData(sqlKey)
      On Error Resume Next
      Dim rs, sSql, sFilter
      Dim rsold
      sFilter = sqlKey
      sSql = ewBuildSql(ewSqlSelect, ewSqlWhere, ewSqlGroupBy, ewSqlHaving, ewSqlOrderBy, sFilter, "")
      Set rs = Server.CreateObject("ADODB.Recordset")
      rs.CursorLocation = 2
      rs.Open sSql, conn, 1, 2
      If Err.Number <> 0 Then
            Session(ewSessionMessage) = Err.Description
            rs.Close
            Set rs = Nothing
            DeleteData = False
            Exit Function
      End If

      ' Clone old rs object
      Set rsold = CloneRs(rs)

      ' Call recordset deleting event
      DeleteData = Recordset_Deleting(rs)
      If DeleteData Then
            Do While Not rs.Eof
                  rs.Delete
                  If Err.Number <> 0 Then
                        Session(ewSessionMessage) = Err.Description
                        DeleteData = False
                        Exit Do
                  End If
                  rs.MoveNext
            Loop
      End If
      rs.Close
      Set rs = Nothing

      ' Call recordset deleted event
      If DeleteData Then
            Call Recordset_Deleted(rsold)
      End If
      rsold.Close
      Set rsold = Nothing
End Function

'-------------------------------------------------------------------------------
' Recordset deleting event

Function Recordset_Deleting(rsold)
      On Error Resume Next

      ' Please enter your customized codes here
      Recordset_Deleting = True
End Function

'-------------------------------------------------------------------------------
' Recordset deleted event

Sub Recordset_Deleted(rsold)
      On Error Resume Next
      Dim table
      table = "age group"
End Sub
%>