Guys, with a lot of efforts and lots of reading here I was able to mode a part:
I made a rectangle and swept some profiles along to create some grooves, the profile I drawn in red.
I want to remove the portion that is in pink from the point to the red line #1, so that I am left with an outline represented by the blue line.
I have started a new sketch and projected the yellow curves from the model and drawn in a line like #1. however I am unable to trim the yellow curves EVEN after I disassociate them from the part they are projected from.
I am thinking that I want to create a shape like #2 drawn in black and for an extrusion to cut out what I do not want. However I m not successful.
However while the 2 distance chamber was able to give me close results, it is not what I want. I need the resulting edge to be parallel to the holes a specific distance.