You could play the Four Swords portion in single player mode, you alternate control of two Links, in the DSiWare and 3DS versions - those versions that Nintendo only made digitally available for limited times.
I wonder if there is a hack that would allow this in the GBA original? I need to look that up now. Lol.
RE: Legend of Zelda A Link to the Past Adds Four Swords for Game Boy Advance Port – December 2nd, 2002 – Today in Video Game History