Rythm formatter custom language plugin

Hi,
I'm currently writing a plugin for IntelliJ which should recognize rythm engine code. It's a template engine where the syntax starts with @.
In my case rythm is mixed with HTML in a .html file.

What is working so far is the syntax highlighting and some HTML formatting.
This is a part of the code which should be formatted:

@extends(XXX)

@section(xxx){
<script src="/xxx/xxx/xxx" type="xxx/xxx></script>
<script src="/xxx/xxx/xxx" type="xxx/xxx></script>
<script src="/xxx/xxx/xxx" type="xxx/xxx></script>
}
@section(xxx) {
<li>
<a href="/xxx">@i18n("XXX.xxx.xxx")</a>
</li>
}
...

---------------------------------------------
And this is how it should look like:
@extends(XXX)

@section(xxx){
     <script src="/xxx/xxx/xxx" type="xxx/xxx></script>
     <script src="/xxx/xxx/xxx" type="xxx/xxx></script>
     <script src="/xxx/xxx/xxx" type="xxx/xxx></script>
}
@section(xxx) {
     <li>
         <a href="/xxx">@i18n("XXX.xxx.xxx")</a>
     </li>
}

So this is what I want:
After the rythm part the HTML part should be indented by 4 spaces. After an opening tag of HTML rythm code should also be indented by 4 spaces. After a closing tag rythm should not be indented.

Any help appreciated.