We can manually add an ALIAS record on the root domain for you. Please be aware that this may lead to your domain unexpected behaviour from your domain as there isn't yet an industry standard for these records, though they are becoming more common.
More information on this topic can be found on the iwantmyname blog:
- Why ALIAS-type DNS records break the internet
- Using ALIAS-type DNS records for CNAME functionality on naked domains, and an easier alternative
Otherwise, you can alternatively update the nameservers of your domains to one of the following DNS hosting providers who support ALIAS and ANAME on the root domain: