How to group/sort an array based on the value of key A?

Question

I'd like to group/sort an array based on the value of key A.

Initial input is like this:

[{A:123, B:"ggg"}, {A:123, B:"fff"}, {A:456, B:"fff"}]

output should be like this:

[[{A:123, B:"ggg"},{A:123, B:"fff"}],[{A:456, B:"fff"}]]

Any insight will be greatly appreciated.