Include nested _include FHIR entities?

I have a Patient with a related patient, > RelatedPerson(s) > Patient

I uploaded a test Patient example, and I’m able to successfully look up multiple includes, as in include organization and relatedperson:

However, I want to get the relatedperson.patient in the same query. I’m unclear from reading the search docs if this is allowed. When I try it on the testing server, it returns a SQL error:

[Microsoft][SQL Server Native Client 11.0][SQL Server]Incorrect syntax near ')'.

It also looks like this server ignores the _include:iterate syntax:

This is ignored. I don’t see “iterate” in the capabilities doc of this server, but I don’t know what to look for specifically.