replace 250 lb propane tank with smaller tanks in parrallel
You can split the system and probably don't need 4 tanks but at least 2. If you are renting the tank and regulator you may need to buy a new regulator. Some states require restraints for smaller tanks these can be as simple as a 4x4 post in the ground with a snap chain to each tank. The post also provides a secure mounting location for the regulator. Some state require tank straps attached to the support a bit more expensive.