Thoughts on the token standard

I think you may be able to ‘be your own middleman’ in this scenario. If services have ‘reserve’ with an sla on that reserve then you can get back all your reserves before you commit them.

if((await a.reserve(concertTicket)) and (await b.reserve(trainTicket) and (c.reserve(hotel)){
   a.commit();
   b.commit();
   c.commit();
} else {

  await a.forfiet();
  await b.forfiet();
  await c.forfiet();
}