Hi there jag2x, next time don't wait 19 months before your next post

Still another way...you could print all three individually, then dry mount them with a large, long over mat with three windows. The borders could be the usual widths, but the width of the vertical mat that seperates the images would be thinner...like looking through a window. Hinge tape the over mat to the board the images are mounted to, tack some dry mount tissue to the images, trim them to final size, place each one in its window, align each (placing something soft and heavy on it helps) tack a corner of the tissue to the mount, then dry mount.