Books in Groups with expandable navigation block

I appreciate the social book module very much.

I'm currently using the social book module for creating wikis.

I missed some features for my use cases:

• I wanted to be able to have book pages as group content type in order to have different wikis in different groups.
• New book pages should appear in the group content stream.
• The possibility to directly navigate to child pages in the "Table of Contents", without having to load each parent page first.
• Creating child pages with one link, without manually selecting the parent page in the node edit form.

So I created a custom module which implements the features above:

If someone is looking for similar features, he is more than welcome to have a look at the current version at GitHub.