I have several div and I try to add more around all 3 elements with append in jQuery : 

I have : 

```
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
<div>6</div>
<div>7</div>
<div>8</div>
<div>9</div>

```

And I try to insert other div like that :

```
<div class="container-1">
    <div>1</div>
    <div>2</div>
    <div>3</div>
</div>
<div class="container-2">
    <div>4</div>
    <div>5</div>
    <div>6</div>
</div>
<div class="container-3">
    <div>7</div>
    <div>8</div>
    <div>9</div>
</div>

```

I tried with append function but it no work, I don't know if is possible ?
Then, I know I need a for loop for this.
Thank you for your help.