In that case you can use Form Initialization Actions or Custom Actions to detect the user's group and set the folder value based on the group permissions. This custom action gets executed when the qListForm loads or when the Save operation is performed. This solution is transparent for the user.
Please check our documentation for more details about how you implement, debug and deploy these custom actions. We also provide a sample fully functional solution that would guide you in building the custom action you need. Check the QWP folder installation and check out the folder pleCode. Also, the documentation can be accessed directly from All Programs->Quest Software-Quest Web Parts or from within the web parts using the "?" icon.
Also make a quick search on this community to find out more details.