First, locate the request and put the request into edit mode.  Next, scroll down to the Administrator section where you will find group options.  

Just click on the group you would like to move the request to and press save.

You may choose multiple groups by holding your Control key down (command on Mac) and clicking on groups.  

If the request is restricted to a group, that would mean that only intercessors in that belong to the group will see that request.