I don't think from a legal standpoint setting up a co-op would be a good idea. I don't think you really need to go to that much trouble. If the other trainers sign the lease they are already liable for their part of the contract. Also, be careful when setting up this type of business structure. The more people you have involved in any particular business the greater the chance for failure. They're is a saying in business, "Partners are for Dancing." And that's it. Most people want to work with a partner because they think that they will get an extra person's effort and help with running a business. This rarely ever works out. Most of the time, one person ends up working harder than the other partner and it ends up tearing the business relationship apart. I would not set myself up in business with anyone other than myself. If you want to get more information on Fitness Business Management, check out my FREE business coaching blog,
www.myfitnessmarketing.com
Dr. Roman