Tutorial Request: multi-Dandiset usage

One of several issue tickets @satra requested to be opened for tracking purposes from the discussion in https://github.com/dandi/example-notebooks/pull/127#issuecomment-3881880703

AFAIK we don't currently have any tutorials that span more than one dataset (except perhaps within related Dandisets like the various IBL projects besides BWM - or the various OpenScope projects)

It might be nice to have a tutorial that showcases some data re-use leveraging two or more Dandisets simultaneously

> finally as a repository instead of using a single dataset, it may also be useful to see how two datasets could be connected, for example similar to sabera's work on creating a timeseries model.

I'm not personally familiar with Sabera's work on this - please attach any useful reference info you think appropriate