Is this possible to do? Video/Custom Type/Custom Categories 3 tiered.

Ok, in my head I can visualize everything so I hope I can put into words that make sense here.

We are building a Private Investigation Case Management System in Wordpress.

My issue I am having is tying things together properly. Here is the look.

PI's upload video or files to default area.
Inhouse staff create a CaseFile (custom content type in WP) and review and assign video to that "post?/page?".

The posts/pages are assigned under different Insurance firms (Categories? Pages? Not sure). So the hierarchy is kinda like this.
- Firm's name
- Case File with attached Video(s)

Now obviously certain ACL's have to be done through Roles/Groups to limit who can access what and who can create etc... which I know plugins for that.

Now I can create each thing, like a custom post a video post etc... But it is tying them altogether.

I am not opposed to paying for help on this either so any and all help or such is much appreciated.

Thank you all in advance