I'm not sure what you mean by the "red icon." IAA (inter-app audio) is not related to MIDI. You only need two things to send MIDI to another app: that app needs to support receiving MIDI from other apps, and that app needs to keep running in the background. You don't have to do anything special in BandHelper.
BandHelper sends to all ports by default, so whether the app listens on the default Network Session, or it creates its own virtual port to listen on, BandHelper's messages should reach it.
The other app would only need to create virtual ports and you would only need to select that app's port as the destination if you need to ensure that the MIDI you're sending to it will not be seen by other apps or hardware. Usually this isn't necessary because most MIDI messages include a channel number and you can set up each recipient to listen on a different channel.