Something like:
List(
Object("foo", 1, "bar", 1),
Object("foo", 1, "bar", 2),
Object("foo", 2, "bar", 3),
Object("foo", 2, "bar", 4)
).GroupBy("foo")
returns
List(
List(Object(“foo”, 1, “bar”, 1), Object(“foo”, 1, “bar”, 2)),
List(Object(“foo”, 2, “bar”, 3), Object(“foo”, 2, “bar”, 4))
)