This functionality is related to POLICY-1427 as JsonPath is planned to be introduced with that tickets to perform filtering operations. 

The usage of JsonPath library to inspect arbitrary JSON structures to perform event filtering has been wanted since previous releases.   The notation used by this library is similar to XPATH.

Ideally, the usage should coexist with the existing limited filtering capabilities from previous releases so to be backwards compatible.   The distinction could be made perhaps in the start of the path, "$". 

If possible commonalities between these two work items should be reused.