I guess it depends on the backdrop.
If you're using seamless paper then cloning out the overlap between the two pieces might be only a minor inconvenience (though tiresome). If you have the luxury of appropriate distance then throwing the b/g well out of focus would be helpful.
If you're using a patterned b/g, good luck. :-(
The simplest would undoubtedly be to get a wider backdrop (along with whatever supports and crossbar you need to hang it), or to find a plain wall or other background that would be wide enough to accommodate the largest groups.