Possible to open a notebook from the extensions API?

The scenario I have is:

A user gets linked to JupyterHub and a notebook is opened with nbgitpuller. Ideally I’d like to just be able to open two notebooks by specifying the repos but that doesn’t seem to be possible, but I’m wondering if since the notebook should already exist in the workspace, would it be possible to use the extensions API to open a notebook by, for example, the notebook’s title?