Yes, you can change the landing page from the default Dashboard where you have the Overview of all Brands and Style Guides (e.g. brand.frontify.com/dashboard) to a specific Style Guide (E.g. brand.frontify.com/hub/1). This is possible on the domain level.
This means everyone that logs in to your domain lands on the defined Style Guide page. Please make sure that everyone has access to that Style Guide as they will get an 403 Access denied error if they are not invited.
To change the Landing Page you can reach out to the Frontify Support Team.