It needs REAL value.
A free tuition session, discounted laps, free ADAC breakdown cover - something to justify that £200 per person.
Hell, I'll book you all into a hotel 10 minutes from the 'Ring, co-ordinate which crossings you're all on, give you detailed maps and pick up/food points and book you into any resaurant you like on any evening...
And I'll do all that for free.