Agreed with blazer_workz comments. We need to complie a list of people who is interested and discuss the date of the shoot and theme etc. Base on the no of people will determine the no of model required. A group of 5 - 6 photographers, is good for 1 model for 3 hours shoot with 2 - 3 attire.
As the group becomes larger, you may have to cater for additional models and re-arrange the duration for shoot. For example, 3 models, 3 hours and 3 group of photographers (4 - 5), each group have 1 hour to shoot the models with only 1 - 2 attire.
Sometimes, we need to cater more time for photographers to shoot. For them, to express their creativity. If less time, will have negative effect and picture may not turn out nice.
This way, we won't stress the model as well.
My explanation is based on experience for your reference. If you need to find models, I will be glad to approach friends from model agencies and organisers. But may not able to get good price, but may have model with standard and experience.
Cheers!