Hi,
Thank you for submitting this idea! This functionality is currently available at the Marketing Hub Enterprise level. You are able to assign an Ad Account to a user or a team. Once an ad account has been assigned, it will only be able to be viewed by those user(s) or team(s) and Super Admins. Users can only edit and publish ads in HubSpot if they have connected their instance of the Ad Account. You can manage access by navigating to Settings > Marketing > Ads then clicking the checkbox next to the ad account that you want to assign to a user or team and click Manage Access.
I hope this helps!
Thanks,
Katie