Update DNS zone group limitations in documentation

Clarified limitations on DNS zone groups for private endpoints.

Author: migmats

articles/private-link/private-endpoint-dns-integration.md

@@ -212,6 +212,7 @@ In a hub-and-spoke topology, a common scenario allows the creation of private DN
 
 > [!NOTE]
 > - Each DNS zone group can support up to five DNS zones.
+> - Each DNS zone group can include only one private DNS zone per DNS zone name. For example, you can't associate more than one private DNS zone resource for `privatelink.blob.core.windows.net` to the same DNS zone group.
 > - Adding multiple DNS zone groups to a single Private Endpoint isn't supported.
 > - Delete and update operations for DNS records can be seen performed by **Azure Traffic Manager and DNS.** This is a normal platform operation necessary for managing your DNS Records.