What model of sound processor do you have? If it’s the Naida CI Marvel, you can stream without an intermediary device, however there may be some latency between sides (speaking of streaming, not free field hearing) .
The only HA, which works in cooperation with Naida CI Marvel (but not Naida CI Q90 or Q70) is Naida Link Marvel, not Audeo Infinio Sphere.
Please insert your audiogram. This may helps to give you proper advice.
I think it depends on which iPhone with which iOS version you have. On newer Android phones I can simultaneously stream to both Paradise 90-RT and Cochlear Nucleus 6 sound processor.