Extending base communication paths

We need the ability to extend a base communication path with another communication path that continues it.

The new (extended) communication path will contain links that continue the base communication path from the last receiver - basically just concatenating the two paths.

We want the database to only store extended communication path links, not copy base path links.

We want to be able to link the two communication path IDs together.

We need to consider what the best way to model this in the DB is. Could be a link table (better approach) or could be that the communication link represents a path instead of a source.

Needless to say, we can have multiple extensions of the same path and multiple levels of extension of one path.

Any API/filter functions and views that work with communication path would need to handle extended paths as if they are whole.