Yes, you can configure a custom content model with your own content type that can allow users to define the main document (let's say parent) and upload (or associate) a set of documents to it.
Consider to have a type named Contract then you could define an association named Attachments where you can drop other documents. Eventually you can also create custom types for attachments or other document types.
Another approach is to extend the folder in Alfresco (named Space) to add custom metadata with your properties to identify the entire folder as a custom type such as Dossier. Very useful when users have to search for that specific set of documents.
More information about content modeling can be found here:
https://docs.alfresco.com/content-services/latest/develop/repo-ext-points/content-model/
