Hi, Marilyn!
I have this exact same problem and have been trying various solutions since the end of July. I have two sets of aid on trial right now, one with Bluetooth and the other with FM. Apparently this problem is unique--or at least that's what I'm told.
Anyway, I think I'm getting to the end of what might work for me. Here's what I've tried:
--a soundboard (like musicians use) with external microphones. This works well with Bluetooth. The problem is that it's way too cumbersome for me as I'm not in the same classroom all the time. The cables are bulky and cumbersome and the mics are on stands. It's not very practical and makes it hard to hear the people right next to me.
--the Comfort Contego functions as advertised but does not pick up sufficiently. I never did figure out if I could add mics before I sent it back. One disadvantage is that it picked up my own voice so much that it interfered with my hearing my students because it had to plug into the Siemens Tek which has to be worn around the neck.
--the Oticon Streamer. Again, wonderful sound, just doesn't pick up a wide enough area. I'm trying to figure out how to add additional mics but have had no luck so far.
--I have a ListenTech FM system on order. I know it will work with conference mics and minimal cables. It will work with my Oticon aids, but I think not the Bluetooth (Siemens.) My guess is that it will take at least three conference mics to cover my classroom, maybe more.
--I also have a four transmitter to one receiver wireless mic system on order that should supposedly work with either the Streamer (FM) OR Siemens (Bluetooth.) Supposedly the conference mics will work with it. This is the ONLY many-to-one wireless system I've been able to find. The gentleman I spoke to said that people who use this have one aid set to T-coil or FM and the other aid set to mic only so that they can hear the person next to them.
As I'm sure you can tell, this has been a long and frustrating road! If you have any ideas or questions, please let me know! It's very good to talk to someone who's experiencing the same problem!
Carol