IPhone accessibility and devices

You can pair more than one set of hearing aids to your iPhone by following these steps:

1. Open the charger and remove both hearing aids to set them in pairing mode.
2. On your iPad or iPhone, go to Settings > General > Accessibility.
3. Scroll up and select MFi hearing devices.
4. Select GN ReSound right and left.
5. Wait for a pop-up that says Pair for each of the right and left hearing aids.
6. Select Pair for each of the hearing aids.

However, the second hearing aid cannot be separately paired with another Blutooth device

I hope this helps!

(Info is limited to my knowledge only)

Or you can just check this page: Can I have 2 sets of hearing aids paired?… - Apple Community