[Exim] Quick Regex Query

hi,

I trying to set a condition, but with no regex knowledge whatsoever it's
proving difficult.
I'd be grateful if someone could spare a minute to put it correct.

Basicly I need to find where "domain.com" (as an example) appears in the
received by headers.

so

condition = ${if match{$h_received:}{somthing here}{true}{false}}

Many Thanks

Andy