Siblings bickering - help me!

[sparkle789]

I have 3 dc dds 12 and 6 and ds 2.
The bickering between the girls is breaking me. It’s endless. They will argue and bicker over anything and I just don’t know what to do.
I don’t know how to deal with it so if anyone has any advice it would be really appreciated before I lose my mind!

Could you set them some tasks that if they work together they get a treat or reward?

Be mean to them all and they will band together against you.

Worked for me and my sisters (though probably not the intended consequence by my parents)