APEX

I have question about checkbox in classic report.

I need to choose only one checkbox in every row, hot to ensure that only one checkbox can be checked at same time?

Checkboxes are defined in SQL query as:

apex_item.checkbox(1,msisdn,'UNCHECKED') as clear,
apex_item.checkbox(2,msisdn,'UNCHECKED') as to_analysis,
apex_item.checkbox(3,msisdn,'UNCHECKED') as to_barring

here is the picture:
http://www.deviantpics.com/images/mNgGR.jpg


Tnx!