Creating a piece to fit through extrusions

I am trying to sketch a closed sketch loop through theextruded cuts in both tubes. I am having a problem sketchingthrough the extrusion on the bottom tube since the sketched circleyou see inside the bottom tube is not in the same sketch as theones on the top tube. So when I am editing the sketch that containsthe circles inside the top tube and trying to add the rest of thesketch through the extrusion in the bottom tube, the bottom sketchand bottom tube disappear. How can I get the bottom sketch or thebottom tube to show when editing the top sketch? Or is thereanother way to go about this?SolidworksParts And Features