The rules seem to support burst-splitting, with the downside of nobody knowing whether the bullets are split and what the range limit is (in SR4, they had to be near each other as well), and the vague language somewhat seems to support attacking the same person with dual-firing. Really wish they'd tell us how that is supposed to work.
After some thought, and a little trial and error I allow burst splitting and spraying at my table...
you divide your dice pool between the total number of targets. Then pick the order of the targets.
For each meter between a target consumes 1 bullet....
The shooter can decide how many "extra" bullets in a burst go to which target.
So for example we have Jose, Brother of Hose B. with an Ares alpha in a complex action (10 rounds) with a skill of 12 (after all modifiers) and 4 targets.
Jose, splits his dice pool between the four attackers....
Next, he declares the order for his attackers: (see chart below)
he determines the distance between the targets (done on the chart)
he gets rid of his "lost" rounds due distance between targets (in this case -7)
Uh-oh! Jose has a problem! due to the distance between his targets, he is out of bullets before he can hit the fourth target!, so he decides to just attack the first 3. (thus giving him a dice pool of 4 per target)
Numbers: (Target 1 here) 3 meters (Target 2 here) 1 meter (Target 3 here) 3 meters (target 4) Total:
Skill pool: 3 (4) 3 (4) 3 (4) 3 (0) 12
Lost bullets: -3 -1 -3 -7
Rounds on target: 1 1 1 0! 3
****
This is essentially the way it was in 4e, and I just transferred it over. It gives FA weapons a little more flexibility and LMGs a large boost (due mostly to ammo, recoil reduction if on a mount) While also limiting the attackers options. (fee action: multi attack, Complex action: the FA burst)
It works fairly well at my table. But of course, is not missions allowed.