On MobiControl v13.x, it is possible to define one add-devices rule per device platform to define device mapping based on LDAP/AD mapping.  As shown in the diagram below, the  last item "Everyone else", which defines mapping for any groups/devices not yet included, cannot be deleted or made inactive.

 

 

Hence, I think it is logically conflicting and thus impossible to have more add-devices rule(s) using LDAP mapping for the same device platform.