Filtering: how to COMPARE SENDER against RCPT

Hello Community Support,

my name is Michael and I am a newbie, thereforebe kindwith me, please.

I also searched before, but did not find some helping answer to my problem, so I will ask here. 

Is there any possibility with transaction-level expression filtering, or general- or global-filtering for that:

seen in Mercury SMTP Server: 

MAIL From:  abc@def.gh

RCPT To:  abc@def.gh

seen in Mercury Core Process:

17:02:10: Job MGxxxxxx: from: abc@def.gh [local] To: abc@def.gh [local] -OK

I want an expression that leads to a reject or a remark in Header (like X-Blocked) if "from" is EQUAL to "to:"

I know that EVERYBODY could be SENDER (and produce SPAM) if the recipient is local, but most of spam (at me) is produced by that sender=recipient.

Do you have an idea for that?

Thank you a lot in advance.

Regards, Michael.