How to split executions in CallActivity

I need to call another process in a CallActivity, which however must not be the continuation of the process, but a separate process with its execution. When I call another process with CallActivity, the “parent” also takes the child process as the next task. But I wish there were no tasks for the parent to do until the child process is finished. The parent and child processes appear to have the same executionId, and that’s the problem. I do not know how to do.

Thank you all,
Best regards.