[exim] Whitelist senders

Hello,

I need to add Shopify SMTP addresses to a senders whitelist. Where and
how should I add this addresses?

I tried with this configuration:

- - - - -
hostlist whitelist = lsearch;/etc/exim/senders-whitelist.conf

(...)

acl_check_spammers:
accept  hosts         = +whitelist

drop    message       = Your host in blacklist on this server.
log_message   = Host in blacklist
hosts         = +spammers

accept
- - - - -

The content of /etc/exim/senders-whitelist.conf is:

smtp.shopify.com
smtp2.shopify.com
smtp3.shopify.com
smtp4.shopify.com
mailer@???

Is this right?

Thank you in advance for your help!

Damon Hill