At one time, LE had a device that amounted to a control board monitored by a commander remote from the snipers.
The sniper rifles had a special trigger system that could only be fired from the board. When a sniper had his sight on the target, he pressed the trigger. When the Commander saw each sniper's light lit on the board at the same time, he knew they were all on the target, and could then press the fire button.
Don't remember if he could fire three or five weapons at once.
System was obviously developed for taking out multiple individuals at the same time.
Don't know if that system saw much use, or if it's even still around. Have heard very little about, but it's long enough to have been perfected if it's currently in use.
However the SEALS did it, it's going to remain their secret while the rest of us speculate.