Unfortunately it is not possible in any NMEA 0183 networking situation to connect the output of more than one Talker to the input of one or more Listener/s.  To convert data from more than one NMEA 0183 Talker to NMEA 2000 you have two choices which are detailed in the following article: https://www.actisense.com/knowledge-base/hottest-articles/converting-multiple-nmea-0183-talkers-to-nmea-2000/