I have one circuit that controls 3 receptacles in the kitchen, and also 3 other receptacles in the nearby living room. When I replaced the first on the run, which is also the one above the sink with a GFCI receptacle, I was not able to get a 'correct' signal from tester. I ended up just pigtailed the 3 black wires, and pigtailed the 3 white wires on LINE side. This allows at least one GFCI protection above the sink.
The next receptacle is the one above the stove, which is less than 6 feet from the sink. Do I also need to replace that one with GFCI? If so, I may also just connect all its wires on LINE side.