In the customer case, the reason they are not seeing URL Grouping applicable is they are just pushing the data through plugin to the EM which doesn't have any Frontend Tracers. Thus URL Grouping won't work.
Release : APM 10.7
Component : APM Agents
Use an application that generates Frontend markers.
The reason being the IA Agent is basically used by NON JAVA Agents to send data to EM. There are many NON JAVA Agents like, Node js, C++ Agent, PHP Agents. All these NON Java Agents have Frontend Marker tracers.
These Frontend Marker Traces generate fronted traces for which the URL Grouping is applicable. This is the reason IA Agent profile still has URL Grouping.