[exim] 2 !hosts or 1 joint !hosts

Hi,

I'd like to set two !hosts checks for my RBL blockings. My conf already has
theese lines:

deny !sender_domains = lsearch;/etc/localdomains
     !senders = @@lsearch;/etc/localsenders
     !hosts = +relay_hosts
     !authenticated = *
     message = $sender_host_address is in the black 
           list at $dnslist_domain\n$dnslist_text
     dnslists = sbl-xbl.spamhaus.org : dnsbl.sorbs.net

I also want to add a white-list check:

    !hosts = /etc/exim_rbl_whitelist

Should I just change this !hosts line to:

    !hosts = +relay_hosts : /etc/exim_rbl_whitelist

Or just make it like this:

    !hosts = +relay_hosts
    !hosts = /etc/exim_rbl_whitelist

Which one is faster/lighter or just working? :)

PS: I think I have to use lsearch;/etc/exim_rbl_whitelist instead of
/etc/exim_rbl_whitelist right?

Awaiting your answers.