InDesign 3page layout?

Hi, I am making a sort of a flyer for this insurance company. The format is a A4 folded twice! So that it has 3 ‘pages’ on each side of the paper folded in a zig-zag way. I made a 3 page master layout with text boxes in InDesign and added text to the first page. It made 4 new pages, because of the length of the text. The first 3 are ok, but the last one is alone on its side an the add page icon only adds one more, so it has only two pages on the side. There is no way to drag the last page there or apply the master so that the 3rd page appears where it should. Did anyone encountered this problem? Does anyone has a solution for that? I would appreciate it very much. :-)