New here and looking for feedback re: Roger Pen, Roger mic, ReSound Micro Mic, etc

In a group of chatting people I need to be able to point a directional microphone to the person I want to listen to. I have the Resound Multi Mic which is very good with few persons attending, but it is not very selective. I would be helped if I could connect my Multi Mic to a directional microphone. I have tried several, but no sound is streaming.
I have also tried if an external microhone could be streaming sound through my iPhone to my hearing aid, but I can not find a setting where I tell the iPhone to listen to the Lightning port and not the internal microphone. Any suggestions?

I use my Roger Touchscreen like this. It works very well. I’m happy.

Hi, thanks for your comment. My Resound MicroMic seems to do the same thing.
What I would like to have is a noise canceling super directional microphone to cover a distance up to 10 feet or more in order to listen to that one person in the middle of chatter and background noise. Maybe that is too much to ask of today’s technology?

I try to find what requirements there are for the MicroMic to accept an external microphone. Another way to go would be to connect the mic to my iPhone and stream the sound from the iPhone to my hearing aid . But there seems to be a problem of how to tell the iPhone to connect to the Lightning port/external mic and not to the internal mic.