Issues with “Generating New Processes” when called by different parents?

[AC Question]

We understand that being with linux kernel, android generates new process and assigns new process ID or each application when launched. My concern is about what happens when the same application is called from different parent processes? and both running at the time. For example user clicked on "login with facebook" for application A and facebook's login activity is started. Now without completing this login, user brings Application B on foreground and clicks "login with facebook" button on this application. Now two facebook instances (or processes ??) are running at the same time. How does the kernel manage process ID in this scenerio ? It seems the kernel doesnt create another processID when its called by separate parent. But how does it manage the single process to act for the different parent ? Does it suspend the previous child when new child is created ??