iControl Rest API - Get ASM Policy Assigned Systems List

Is it possible to return a list of assigned systems for an ASM policy? We have a large number of policies that I would like to do some reporting on, and part of that analysis determining which assigned systems are used and how many policies use them.

The closest I can get is to get a list of systems that a particular signature belongs to, however that won't work as the list contains systems that are not assigned to the ASM policy. I've read through the API documentation and I can't seem to find an endpoint, or a collection of endpoints, that will return only the systems assigned to the policy.

Thanks in advance!