I have also encountered this problem. having special_context_id/special_package_id, isn't as flexible as it should be if you ask me. You might want multiple summarizer instances that selectively choose info from other instances (look at project-manager as an example of integration with logger). So a rel_type where a one package_id to many package_id would make more sense to me.

The easiest way to do this if you ask me is to put a package specific parameter, or set of parameters. Then you wouldn't have to re-write the display view pages at all, you simply say, on the index page, display all events from parameter (ShowOtherInstances): 123 345 567, and the sql query does a display all XYY where package_id in ('123','345','567') where there is public read permission (you would probably want it to display the current package and any additional package_ids). This lets you maintain permissions accross packages at the package level, and for that summarizer instance you could simply state that nobody has permission to add an event/presentation - so it would make wimply a display only instance. This would let you for example have a math-wp instance that shows all math related wimpy point instances, and an english-wp instance that lets you summarize all english deparment instances, etc.