Non software related problem: Nested Structure and Compound Symmetry

[eza494]

Hi all involved

I like this package quite a lot and I was wondering if its possible to define the following:

1. Multilevel random effects such as nested and crossed.
   For example schools and classes with classes being part of specific schools for multiple different schools
   For example: patientIDs (1-5) part of experiment 1, patientIDs (6-10) part of experiment 2
2. Is there a way to define compound symmetry/exchangeable and unstructured covariance structures.

Kind Regards