获取以相同字符开头的行

Question

I have a file that looks like this:

    acquaintances       Bekanta
    acquaintances       Bekant
    acquaintances       Bekanting
    acquaintances       Bekantskap
    acquaintances       Umgängesvän
    acquaintances       vänkrets
    acquaintances       vänkretsen
    adoption        Adoption
    adoption        Adoptionen
    adoption        Adoptioner
    adoption        Adoptering
    ...

and I want to make it look like this:

acquaintances:      Bekanta
                    Bekant
                    Bekanting
                    Bekantskap
                    Umgängesvän
                    vänkrets
                vänkretsen
adoption:       Adoption
                Adoptionen
                Adoptioner
                Adoptering

（不同的缩进是故意的）

我一直在试图弄清楚如何选择以新单词开头的行并替换它们。这是我得到的结果，但它不起作用：

Find:
^(.*?)  (.*?)   (.*?)
\1  (.*?)   (.*?)

Replace:
$1  $2  $3
    $4  $5