gnus question; how to make coming mails to be read

[Kiwon Um]

Dear emacs gnus users:

I'm now using gnus with pop3 of gmail. Using nnmail-split-fancy, I
split sent mail into specific group mail.sent. As you know, if I send
a mail using smtp or web of gmail, it sends back the mail to me, and
it goes to mail.sent as I set the nnmail-split-fancy. This is okay for
me. In gnus then, it becomes the new mail so the gnus-notify+ notifies
it. However, in my context, it's already read mail to me.

So how can I make these mails in the group (mail.sent) to be read (or
expired) automatically?

Please give me advise.

Thanks.

--
Kiwon Um