How to retrieve cor/rescor from nested models

I am fitting mixed models using Stan.
Model with one random effect, the random part of the model looks like this:

(1|p|ID) #cor/rescor in output.
(1|ID) #no cor/rescor in the brms output

How do I code this with nested random effects when I want to have cor/rescor in the output?

(1|p|Observer/Tank/ID) #does not work
(1|p|Observer/p|Tank/p|ID) #does not work.

Thank you very much in advance!