[exim] Ip whitelist per domain

Hello,

I am trying to have lists of IP to be whitelisted per domain.

This was doing the trick quite fine

  warn    hosts         = <; ${expand:${if exists {PATH/ip_wl/$domain} \
                             {PATH/ip_wl/$domain}{}}}
          add_header    = X-wh_IP_: Yes

but in fact it restrict the number of RCPT exim can handle. If this
number is exceeded I get an error
"string sprintf expansion was longer ..."
and
"expansion started "
in the logs.

This apparently comes from how domain is set when there are multiple
RCPT (moreover if all RCPT are not for the same domain)

I tried really hard to get it done with iplsearch which seems to be what
I need but I couldnt figure  out the right way to do so .

Has anyone ever had to do something similar ?

Thanks in advance for any help
Best regards