You can add an attribute to specify the navigation status in your content class and set them to different values in content objects. The attribute type and meaning depends on your requirements. For example, you can define a check box in content class to specify if it should be shown in navigation or not. You can also define a text-line attribute as the navigation link URL, and if the navigation link is empty, the default $node.url_alias will be used, otherwise, the specified URL will be used.
Does it answer your question?
Michael Lee | Managing Director | ZerusTech Ltd | www.zerustech.com
your solution surely will address the problem, but it involves some extra work from content editors and from programmers to enact it. I hoped to find a more structured and robust. solution that will ease the burden on the users.
Yours will surely work; but I don't want to change 30 content classes and manually set all those flags for all the content objects I have :) (currently 1000 and not easy to write rules to do that in a programmatical way - except for to check for which templates is the node using, which again puts me back to my original problem).