I have a domain, example.com, with the dns records hosted with Google Cloud Platform.

Is it at all possible to make a subdomain, ddns.example.com at Google, somehow set Dyny nameservers for that subdomain and have that subdomain used for ddns here at Dynu, using subsubdomains, like foo.ddns.example.com and bar.ddns.example.com?

Since I have posted this I have found that it is possible, by making NS records for the subdomain there the DNS is hosted for the domain.