I've done quite a bit of this, two ways. One is to print separate images, cut them for best crossover match, then drymount with a very small space between each image (no more than 1mm) between. Then cut one big matte window to fall just .5cm or so outside the edges of the prints. I find that trying to make the seam invisible (like butting the edges together) doesn't work, looks goofy, and if any emulsion chips off at the edges, it's really noticable.
Some gallery owners have recently told me that dry mounted prints are undesirable to collectors (can't unmount, etc.). So lately I have been trying to cut the prints so that there is an overlap at the crossover of about .5cm. Then I cut a window in the matte for each image. Cutting from the back, I try for 8mm width between images, a bit narrower from the viewing side with the bevel. It's a lot of work, but then the prints can be hinged and the collector can remount if desired. Frankly, I like the look of the drymounted way. I can always sell another set of prints to a collector.
I have also printed multiple images on one sheet (up to 9, when I was in college and had the stamina). As some have said, it's a lot of work, and artistically, it's a different statement, accepting some of the imprecision of the crossover in favor of the single print, with the matte covering the edges of the print, but just outside the silver image, the desired form, from what I'm told. Try different things in small scale, and pick the one you like. If your images are successful, it won't matter. (The purists may grumble about your drymounting a 100 years out.)