attendee list for appointment

Hello

Does anybody knows how to customize behavior for list of attendees for the meeting (CRM 2007) ?

I am talking about appointment (leading transaction category BUS2000126 Business Activity)

Partner determination procedure works for 'parties involved'. if we add new partner to the list of 'parties involved' it goes automatically to 'Attendee' list. If we remove this person from 'attendee' list it goes automatically away from list of 'parties involved' . We do not want that. We want to have option to keep somebody in the list of parties involved, but not on list of attendees.

regards

Rafal