By default, a domain's DMARC policy applies to all of its sub-domains. DMARC allows you to apply a different policy to sub-domains if you wish; however, whichever sub-domain policy you specify will apply to all sub-domains. If you want a different policy for specific sub-domains, publish a DMARC record specifically for that sub-domain.
What policy do you want to apply to email from a subdomain of this DMARC record that fails the DMARC check? This will default to whatever policy is applied to the organizational domain.