I noticed that there new support for host-record in development It would be nice to also support CNAME to make restricted search possible.
https://github.com/pi-hole/pi-hole/pull/2978
host-record=safe.duckduckgo.com,50.16.250.179
cname=duckduckgo.com,www.duckduckgo.com,safe.duckduckgo.com
cname=duck.com,www.duck.com,safe.duckduckgo.com
https://discourse.pi-hole.net/t/use-dns-to-force-youtube-into-restricted-mode-and-pi-hole/1996/31
It is not in the future database so groups is not possible.