Unfortunately PD4ML does not support the feature.

Of course the index creation cannot be fully automated. Let say you mark all significant keywords like that:

text text keyword text text

Currently you may generate PDF bookmarks from the markup (pd4ml.generateOutlines(false)). The bookmarks give you quick access to the marked keywords. However the bookmarks are not sorted as index assumes and they are visible only in Acroread, not in print output.

Obviously we need to add a new proprietary tag in order to support the feature you need. Also the keyword markup needs to be extended with a switch to make possible exclude regular document anchors:

text text keyword text text

or to introduce another tag for that:

text text keyword text text

If the above is acceptable by you we’ll include the feature implementation to our plans. The priority will depend on the license type you are going to purchase.