DeletedUser471 IPC between apps on the same profile can not be currently disabled/is not implemented. There are certain fundamental functions of apps that allow them to communicate with other apps that when disabled, they would no longer work as they should.
There is no IPC between apps on separate profiles because they are delegated to different sandboxes.
But if the same determined app for instance is installed in multiple profiles, it has a way of correlating those through certain hardware identifiers, performance data and global configuration.