bind applications to activities?

How can I start an application on a specific activity? And how can I start an activity always with a specific application? I am quite sure it was possible in KDE 4, you could assign applications to activities - but I don’t find it in Plasma 5. I’d like to have a Gimp activity which always starts Gimp - or when I start Gimp it opens that activity…

I only know that if you start an application on a specific activity and if you stop that activity it will start that application when you start that activity again.
Despite that when right clicking on the icon in the titlebar and choosing special settings for application you are able to set to open this application on a particular activity.

Ok, I see. So there are no special activity settings for application sets anymore, it relies on a kind of autostart feature… That’s no quite what I want because I tend to close my applications. I’ll keep inverstigating :). Thanks for the hint with the special application settings.