[exim] Blocking hosts by (false) hostnames

Hi,

is there a way to deny incoming mails from servers with certain (false)
hostnames.

I have many entries like

2021-02-26 06:41:37 H=(upc.at) [109.237.101.160] F=<Elon-Musk@???>
[...]

which I currently block either by IP or incoming e-Mail-Address, but I'd
like to block all incoming mails from servers who announce themselves
as (upc.at).

Thanks! --- Jan.