Community Group Size for Efficient WASH Management

I'm going to be working on a WASH project in Colombia with a rural community of 750 people. They have water scarcity issues part of the year, and we're working to help them obtain water year round. Community involvement is very important to our philosophy, and I'm trying to figure out how to manage 750 people. With that many people, it would be almost impossible to have a community meeting, and we'll want to have a number of them throughout the project. I'm thinking that the process would work better if I divided the community into smaller groups. 5 groups would be 150 people per group, and 6 would be 125. While it would be encouraged, not everyone will come to these meetings, and some are children, etc. So the numbers at the meetings would be a bit lower. I was wondering if anyone has dealt with a situation like this, or has an opinion on how big a group could be before it becomes inefficient?