php - 配列を同じ要素値で結合し、それらをまとめて保持する

Question

私はこの配列を持っています:

[0] => Array
    (
        [userid] => 208
        [username] => sara
        [email] => sara@sara.com
    )

[1] => Array
    (
        [userid] => 4
        [username] => jack
        [email] => jack@jack.com
    )

[2] => Array
    (
        [userid] => 303
        [username] => michael
        [email] => michael@michael.com
    )

[3] => Array
    (
        [userid] => 208
        [username] => joe
        [email] => joe@joe.com
    )

[4] => Array
    (
        [userid] => 208
        [username] => david
        [email] => david@david.com
    )

そして、私はこの結果が欲しい:

[0] => Array
(
    [userid] => 208
    [username1] => sara
    [username2] => joe 
    [username3] => david
    [email1] => sara@sara.com
    [email2] => joe@joe.com
    [email3] => david@david.com
)

[1] => Array
(
    [userid] => 4
    [username1] => jack
    [email1] => jack@jack.com
)

[2] => Array
(
    [userid] => 303
    [username1] => michael
    [email1] => michael@michael.com
)

いくつかの foreach と $n++; を使用して、array_combine、array_merge、さらには array_unique を試みています。成功しないサイクル。より正確には成功しましたが、配列の構造全体を変更しました。