The simplest would be to put two in wall speakers at ear level pointing to the sofa. And then balance the output with a sound meter so equal output reaches the ear of the person sitting on the left facing position on the sofa.
The hallway doors will need to be closed.
If you're able, it would help if you went with a 7.1 system and had bi-poles above the sofa and opposing speakers at ear level.
Hope the above helps.