Scroll down a bit and there is a thread on Chionactis (shovel-nose snakes). They are a sand dwelling desert species that feeds on insects.
Ringneck snakes typically are found in much moister environments. Diet depends partly on what type / subspecies of ringneck your dealing with. Some specialize in salamanders, some will take worms and others like to feed on other snakes.
Because of their radically different environmental requirements, ringnecks and shovel-nose snakes would be incompatible. Your shovel-nose could also wind up as dinner for your ringneck.
I recommend getting a Peterson field guide for the region you'd like to collect / obtain snakes from. Read up on the diets and environmental requirements of different species and use that information to decide which species to try. Also keep in mind that many of these species are seldom kept so there may be little to no information about their captive husbandry available so you will have to "learn by doing" in order to get your snakes established.
I'd recommend just starting with one species intitially and make sure it is well established before adding a second. It would also be best to not only get snakes with similar environmental needs but from the same location as well. This will minimize the chances that one species would be harboring a parasite or pathogen which could prove lethal to the other.
-Alice