I'm requesting for a option, that if enabled, allows two people to use the same computer simultaneously, with two cursors by detecting two mouses and two keyboards, and multiple active audio outputs (Bug 496210). It should only be possible with two or more monitors, since having one focus per each monitor is organized and clear. This requested option should be a "set co-op account" located in the Session Manager, allowing to set which user accounts will participate and have access to these shared files.
Additionally, each user should be able to isolate their audio from the other user, so one user can listen to audio without having the other user hear it.
This is an interesting idea, but it's pretty far out of scope for what can be tracked in a bugzilla ticket; you're requesting an entirely new usage paradigm for desktop computers. In order to work tolerably well and not introduce impossible-to-fix bugs through all levels of the software stack, this would be a multi-year engineering effort. See also https://community.kde.org/Get_Involved/Issue_Reporting#Step_1:_Make_sure_it's_a_valid_bug_or_feature_request