I have a child like this in my care, who will just scream really loud- I mean LOUD! and she can't be spoken to or redirected. I have also experienced this is childcare/preschool settings from children who are 3 + older.
I have told the child that when they are ready I can help them, but right now they are to loud. Usually other children will comment about how loud it is, which I say they are right it is loud, and I try and offer another area/spot for the non-tantrum children almosting leaving the crying children away from the group. It is not exclude the child, but to help the other children so that they aren't bothered by it. Almost within 30 secs- 1 minute the crying child will notice this and want to come with us, but I will tell them if they want to join they need to stop screaming/crying because the other children can't enjoy themselves.
Also taking notice to what sets off tantrums, and being aware of what are appropriate expectations for that age group. You can't expect a group of even 2 children under 4 to be able to problem solve how to share toys, that is unrealistic. That is when you want to offer help when you see the situation escalating BEFORE it becomes a scream-fest for toys.
I have done this method 2 times with the child in my care and haven't seen it again in a while.
With my own children, once in a while it happens, but only once that day.