Launch same application with different .desktop (and icons) task manager

Suppose I have a program myapp. It has two sub tasks, A and B. Launcjhing myapp --task A launches A and similar for B. Launching myapp only opens another intro window. I have three .desktop files in /usr/local/share/applications: myapp.desktop, myappA.desktop and myappB.desktop; all with different icons. When I launch myappA from applications menu in my desktop environment, it opens task A but the icon shown in plasma task manager (or dock in gnome) is of myapp.desktop. Also if I run myappA and myappB together, they are grouped together (I can prevent grouping but that will not group two task A windows also). The behavior is consistent in KDE, GNOME and other DE's. So is there any way to have three different icons for task A, task B and intro windows in task manager?