Sure there is. You need to call the Monitored Entities v2 API to fetch information about any entities. For example to query OS Type for a host you need to specify +properties.osType in the fields query parameter.
Be sure to use API client for the API such as dt if it fits your scenario..
If you want to to query OS type of a process group, you can query it using relationships. For example to query HOST running a PROCESS_GROUP_INSTANCE: