Some deliberate practice might help? Training sessions to simulate the distractions where the aim is just to keep focus. Also, do as many mass start races, relays. loops races etc… as you can. I mean, it doesn’t give you a ‘thought process’, but it does familiarise you with the pressure, which must be a large part of the battle? Even armed with a thought process you’re still going to need to practise it, right?
I’ve often wondered whether we in NZ just don’t get much practice at running amongst other competitors? I assume that in parts of the world where fields are larger there are more runners on your course and more runners total, so concentrating whilst around other people is just a natural thing?
Anyway, best of luck with it. I’d be interested to hear how you get on, or if anyone else has been down this path before.