Help! Need to Set different Image Folder

I have a Joomla site where I use FCKeditor for members to add content, but need to restrict access to a specific image folder when they upload or add images (I don't want them using my site's regular images). Currently, FCKeditor defaults to the general Image folder providing access to all of my images. I have created a folder called images/member_images that I want FCKe to default to. How can I set this up? Thanks in advance for any assitance.