nnieto Sure, just add a wildcard subdomain like
*.domain.com and assign that subdomain (and only that one) to a site with LE enabled. The generated certificate will be valid for
*.domain.com and you can assign it to other sites (like
www.domain.com) if you want to.
The downside is that those other sites won't be using our automatic LE management (since you're manually assigning a certificate) so you'll have to update them every time the certificate is renewed.