Is it possible to have both on-premise Active Directory integration with users being provided from AD and have other users in Okta UD that are not in the AD?

Both sets of users will be accessing the same applications. The users in UD will use Okta Groups not AD ones, while the Users from AD will use Groups managed in our On-Premise AD (and integrated with Okta).

Why? We have two distinct groups of users some are internal staff members we want to manage in AD on-premise, and rest (majority) are external temporary staff we do not want to manage on-premise and would prefer to use Okta UD to manage.

If we can not do this could someone provide a link to documentation that clearly indicates this is not possible. Currently the assumption is that this is feasible we have not seen any mention that it is not.