Speaker set up for more than 1 person

You can try extreme toe-in so that the speakers cross well in front of your listening position.  The person to your left will be closer to the left speaker, but, now that speaker's dominance is mitigated by that listener being way off axis to the left speaker and more on axis to the right speaker.  This compensation helps with providing a more balanced image for the off axis listener.  

You could also make the two guests sit closer together by putting one seat dead centered between the speakers and two chairs close together behind that centered chair.

Obviously, setups to widen the sweet spot will compromise the sound as compared to the ideal setup.  I am not saying extreme toe-in will not hurt the sound, but, it would be the easiest temporary compromise for when you are entertaining a small group of listeners.  I have helped with a number of audio show setups, and that is what is employed because the listening chairs are set up practically wall to wall with most listeners WAY outside anything resembling the sweet spot.  If you can, put a low chair dead center between the speakers, and slightly taller chairs close together behind that center chair.  This will deliver respectable, if not ideal, sound.

Depending on how critical you are about what constitutes the sweet spot, that spot can be very small, as in only a few inches wide.  This is the case with almost ANY speaker and room setup with the possible exception of omni-directional speakers (e.g., MBL speakers).  The closest I've ever heard to a system that could deliver a decent stereo sweetspot for two listeners was a giant system (speakers 4.5 ft. wide and more than 8 ft. tall) in a dedicated listening room that was about 25 feet wide by 45 ft. long.  

Yes, as I have said above, the toe-in approach is, at best, a compromise, but, there are few things that can be done for what the OP is hoping to accomplish--it is crazy to suggest buying different speakers, for example.  

I recall that there was one commercial model of speaker specifically designed for the time/intensity tradeoff to widen the stereo sweet spot.  It was a speaker made by Leslie, the same people that made organ speakers that spun to create interesting effects.  There home audio speaker line was not a commercial success.