Get Child Activity Instance tree via Activity Instance ID

Hi,

Is there any way that I can get a Child Activity Instance (Tree) similar to the childActivityInstances that this API (Get Activity Instance | docs.camunda.org) returns, but uses an Activity Instance ID instead of an process instance ID via REST APIs?

In my scenario, I have multiple event subprocesses inside a multi-instance subprocess that I want to check if what event subprocess are started/active using the activity instance id of the multi-instance subprocess.

Thanks,
Jan

I wonder if you received a reply or found a solution. We have a similiar problem.