I have been reading some of the documents and other forum posts about Mandanten and Security Folders.
From my understanding just using Mandanten would work well for what I want to do. Although I am not 100% sure how far I should be editing scmandant and scsecurity to separate all the companies. Would the following be redundant to do or is it the proper way of accomplishing what I want?
Exclude: All other Companies
File Name: company
File Name: Operator
File Name: contacts
File Name: (incidents, problem, probsummary, rootcause, request)
Add Security Group to all users in CompanyA.
Rinse and repeat for each company in HP Service Manager.