Fermata only on particular staves

I’m transcribing some Massenet’s Opera excepts. Massenet use fermata only on particular staves.

I really like the Dorico’s way of managing fermatas and how it automatically add a fermata to all staves.

Does anybody know if it is possible to add only on a particular stave ?

Not at present, I believe. Your best bet for that is a custom playing technique.

could you elaborate on that? How do I set a custom playing technique up?

Try this video for starters, and also pages 106-110 in the Dorico 2 Version History PDF.