Midi thru with multipe arduinos

this is the schematic I found for the midi thru interface, now I want to replace some of the 'thru's' with arduinos so that each arduino gets the same input messages but will all output something different, do I need to run the inputs from the first trigger/inverter to the arduino inputs, or do I need to send the input from the second trigger? (example let's say I have 3 arduinos thy need to get the same midi in from the optocoupler, so after pin 6, which is usually sent to the arduino input, I send the output from pin 6 through one trigger, then do I need another trigger for each arduino I add?)