Starting a news agency?

A service similar to AP, Reuters and Bloomberg but only focused on the travel trade in South Africa.

Intend using freelance journalists and contributors who will provide exclusive content and be paid per submission. Content to be sold to news and related companies.

What do you think of the concept?
What would be needed to make it a success?
What shortcomings should i guard against?
Who determines rates for contributors?
What attract news companies to pay for content?
Who owns the content, newswire or contributor?
What is the best way to market such a service?