Is there any way I can setup a joomla menu with different templates depending upon the usergroup.
For example, guest user see that menu in with template A layout and registered user see the same menu in different template.
There might well be a neater way than this... But a roundabout way that would work would be to create two separate menu items that have different templates assigned to them and different user permissions but still in the same location in your template.
Eg menu item 1 has template 1 and permissions are set to guest and menu item 2 has template 2 and permissions are set to registered.
Disadvantage is that you would have two maintain two sets of menus, which I am guessing you would like to avoid and are seeking a neater solution for.