Long time lurker but I may be able to help here. I run drift days mostly based out of Taupo, we have done a number of days where what we have done is split the field in half and dont 1 group of drift and 1 group of grip (usually for a bunch of people who want to go play together or from a club who dont feel they will have the numbers to support a day on there own) so am happy to help out on that sort of front.