Is there any way to use multiple subdomains from a single parent domain?

For Example I already have configured a domain called mydomain.com with a vercel project.
Can I add subdomain.mydomain.com and subdomain2.mydomain.com for 2 more vercel projects?

I have tried to add a subdomain subdomain.mydomain.com but it says mydomain.com domain is already use for one of your projects.

I was expecting that after using mydomain.com for one of my projects, it should allow me configure subdomain.mydomain.com for 2nd project and subdomain2.mydomain.com for 3rd project…