After some focused time on implementation, this all works now. After starting to use it, I found the need to manually add an incrementing integer on every group along with most posts having a separated date components to be redundant. It would be really great if there could be integrated support for date strings, since that's such a common use case. I actually implemented this last night with an optional date component and an un-numbered tag component, but that ran into a missed consequence where, even though I could pick and sort items into a list, they no longer had links to prev/next elements. What I really need to do is be able to tell a "group" to use some other value as its ordering. The important thing is that we're not just using this data to dynamically query objects into lists, but to make multiple coexisting canonical sequences. This means that every group will need an index to order itself on, and that a tag can still exist but provides no navigation semantics.

To be honest, perhaps I should just add a way to say "use the date" on a group id and let the date just be a special bonus way of using the system as it was before.