Grouping of KM custom properties

Hi SDN,

We have created three custom properties for KM files e.g., abc, pqrs, xyz. These three properties are of boolean type and so they appear as separate checkboxes in the miscellaneous tab of KM file. Instead I want to group these properties into a single property (checkbox group) called "alphabet" and have these as check boxes under this field. While saving the file, atleast one checkbox should be checked.

Other scenario, I tried out was creating a property called "alphabet" of type boolean. The allowed values under it are abc, pqrs,xyz. I have set this property as mandatory. So if any of the checkbox is not checked, it throws error message. But by this method, I am not able to retain the values selected.

How can I achieve checkbox group field in custom KM properties?

Thanks & Regards..,

Ganesh N