On one wall, in a line, there is a toilet-works fine, bathroom sink-works fine, tub-drains fine, bathroom sink-won't drain and no luck with a snake, toilet-works fine, but bubbles up when the first toilet is flushed. Kitchen sink on the back side of the first bathroom sink drains fine. Should I call a plummer? I am so afraid that they will have to tear out the wall. Any suggestions?