0. which country are we talking about here? americas, uk, somewhere else? in any way, you will need to know local regulations for becoming and operating public service provider.
1. you will need to establish a company (firm, commersant, ...) to deal with middle-mile provider.
2. as a head of company you will need to consider your business - financial aspects, sustainability, etc. (it may be that you could do it as offhours project, may be not :)
as alternative, if you could persuade that middlemile provider to sign an agreement with you as individual, you could arrange some cooperative type of service. (if you are smart enough, and neighbors are willing)....