[exim] SPF and sequential exims.

I have two hosts statler, which is a primary MX which passes mails on to two
backend servers. One of those servers is scooter which in turn is primary MX
for some OTHER domains.

Scooter has the following SPF-check

deny
    message     = [SPF] $sender_host_address is not allowed to send mail \
                  from $sender_address_domain.
    log_message = SPF check failed.
    set acl_m9  = -ipv4=$sender_host_address \
                  -sender=$sender_address \
                  -helo=$sender_helo_name
    set acl_m9  = ${run{/usr/bin/spfquery $acl_m9}}
    condition   = ${if eq {$runrc}{1}{true}{false}}

But, it now seems that if a domain that HAS SPF set up and the mail gets
relayed through statler, it gets rejected. Probably because statler is "Not
allowed" to send mails for that domain.

Is my assumption correct? And if so, can I do something about that, except
simply excluding all mail that comes in from statler from the above check?