I've got a horsey dilemma!?

Basically, I love riding but I hate just having a lesson. I want more from riding - I want that feeling of bonding with an individual horse through looking after it etc. However, I cannot loan or own my own pony and I wanted to know whether there was any other way that I could 'get' a horse to just look after and ride etc. and be given the freedom with because that's what I want from horses, not just learning how to ride. So basically, I'm just asking whether anybody knows of a way I can do that; through organisations or charities etc. I really miss having my own pony :(