XPages checkbox group - binding to a hashmap

I have a Hashmap (sessionScope) containing the names of guests and their UNIDs.

For example, in the hashmap below, Carmen Adamson is the key. The values of guests in her cabin are: Carmen Adamson and Stephen Adamson. The alias for each checkbox field is the Guest UNID and the values are separated by a "~".

CARMEN ADAMSON STEPHEN ADAMSON | 1C145A291A5DFEC188257E200071402E~CARMEN ADAMSON | 813B80C332EC192188257E2000714030

Can someone help me with some example code on how I can bind a checkbox group field directly to a hashmap?

Thanks so much,

Dan