Movie/Video Texture

I need to make a "game" that just allows me to swap between video textures seamlessly by pressing different keys on my keyboard. For example Say I have a video of a flower up and next I can choose from my library of videos. I can hit the "n" key to swap to a polar bear seamlessly once the flower video is done playing. Its kinda hard to explain but please help me figure out how to do this! Thanks !! Justin