You can take a look at this KB -How to customize the indexing of html documents.
I am not sure whether it will help or not, but let me explain you how the index works. In Sitefinity there are two types of Index providers - ContentIndexProvider and PageIndexProvider
ContentIndexProvider - uses Generic Content API and it always uses shared content items. Shared content items are items created through a Generic Content based module
PageIndexProvider - it makes HttpRequest and gets HttpResponse. As a result the entire HTML of the page is indexed. In this case there is no difference between the objects - shared, not shared - just a text, whether they are from any other module etc.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items