It sounds great on the surface, but it doesn't actually seem to be 'decentralized,' at least not entirely. You say that there is an individual 'jar,' a group 'jar,' a regional 'jar', etc. It sounds to me almost like a pyramid organization rather than a decentralized system. Very cool idea, though. Has anyone in your group actually had to use the regional or higher jar? Just wondering what the actual experience would be like when it is needed.
RE: A decentralized solidary group as an alternative to health insurances. Artabana.