My kitchen sink, sump pump, and washing machine all use the same drain line that is currently not vented. When the sump pump kicks on it blows bubbles in the kitchen sink, then when it shuts off it siphons some of the water out of the trap and gurgles. There is no toilet connected to this line. It's just a straight leach line. Here's a picture of the plumbing in the area. I don't have a way to get a vent up through the wall so I was thinking about going through the floor joist on the left to get outside then up the side if the house to just below the eave. My question is which 1.5" line should I hook the vent to? The line in the left is for the washer and the one that goes up through the floor is the kitchen sink. The sump pump is the 3/4" line on the right This drain system is not connected to the bathroom in any way. Thanks for the help.