Hi @Caroline1020 I hope you are well.
There is no way of getting the reviews from one of your listings to the other really.
The reviews of both listings are united on your personal profile which guests should click on in the process of checking-out your listings and history.
I screenshot and add some of my best reviews into my photostack, at the end- you could do the same- and state the reviews are for the sister listing in your property.
Have a look at my photos on my listing (5* luxe room..)and click right through to the end to see what I mean!
Paul 🙂