It is always the price for the whole group:

Experience without actor
2 persons cost 69€
3 persons cost 89€
4 persons cost 99€
5 persons cost 109€
6 persons cost 119€

Experience with actor (possessed)
2 persons cost 79€
3 persons cost 101€
4 persons cost 114€
5 persons cost 127€
6 persons cost 139€