I don't believe they can as they are different species. But a male swordy will try. You might think about getting him 2 or 3 girlfriends of his own type if you have room.
Could be an interesting experiment, but it could take several months before you see any results. Keep us posted if you give it a try. I was thinking of getting some platies when I get my big tank and having the 112liter for just livebearers.