I see two. I do not discuss one with the other. They are both psychodynamic but I discuss different things with them. They sort of generally know the other exists but that is it. I do not see it as mandatory to tell them.
My question would be - why would you want to do so? What benefit would there be for you in doing so?
For me, I told the one I was seeing others because she was failing me in an area and the other knew I was interviewing various therapists because of the first one being inadequate in some ways (I did not go into specifics)