This might be a great rescue story with a little bit of help

I am not a great writer, however I will try to explain the situation that is currently happening in our life. We are a happy family: my husband, myself who is expecting our first baby and our cat Alisa. We live in a city of North Bethesda, MD in a townhouse and as i mentioned above we have our home neutered female cat on our own. During the last two months we noticed a huge black feral with bold patches all over his body that comes to our house and sprays all over the front door, the back door and the garage. Neighbors said that he has been coming from time to time during the last 3-4 years, but since we bought this house recently and moved in with our cat he became an "almost every day guest" at our community. We tried to set up a cage-trap "Have a heart", tried to use various cat sprays and nothing helps. This is a cry for help. I am currently 9 months pregnant and every day I clean his urine marks because the whole house inside smells like a huge cat toilet. I know how dangerous it can be and I am simply terrified... we contacted numerous organizations in Montgomery County, MD and we just keep getting transferred with no result. My family is willing to help this abandoned cat, my mother-in-law can adopt him if he will be neutered. Currently our life is a mess with all this daily cleaning and scrubbing and we can't get any help to catch this feral cat to simply give him a good loving home. Maybe someone can help us and suggest something...Thanks a lot PS: On the picture is our own cat. Unfortunately I can't take any pics of the feral since he prefers to keep the distance.