Last received email in case changing status

[Emmker]

Hi.
I have created a "need reply" status in cases.
The goal is to automatically switch a case to "need reply" status whenever the last email in the cases stream is from a third party (customer, vendor, or whatever) and not an answer from our agents.

I tried to do it with a report with filters: emails.is Replied (yes)
but that gives me the cases with my agents replies also.