Leeres Gruppenkabel einfügen

After selecting two cable cabinets and specifying the cable length, a group cable is inserted between the two cable cabinets. It really doesn't matter in which order the cable cabinets are picked, except that the Y position of the group cable is determined by the picking point on the second cable cabinet. Attributes associated with the group cable include information on cable length, amongst others. The group cable is not associated with any cable type; it remains an "unknown cable".