Thank you for contacting us.
Is possible to use multiple AD domains. You need to create connections and providers for each AD domain. After that, each provider will be available in the dropdown for the backend login. Follow this documentation to configure the default LDAP and then the additional ones:Configuring LDAP settings
If you have further questions, do not hesitate to get back to us.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items