Project is a set of ear enclosed headphones for the hearing impaired for the purpose of hearing the television without using other hearing aids. Because the listener (hearing impaired person) doesn't wear hearing aids while using headphones to listen to the television, it is very difficult to communicate with the listener even if they take the headphones off because they're not wearing their hearing aids. The headphones would need to connect to the television just like many on the market using Bluetooth. They will also require an external microphone for others ([login to view URL] etc) to be able to speak into with either a press of a button by the listener or some other method that reduces or mutes the sound of the television while the person speaks to the listener.
17 freelancers are bidding on average $375 for this job
Some BT audio MCU such as CSR series has fumction that can select different line-in to the line-out. The function you desired can simply modify the BT headset to achieve.