I think you'll find REXJET are charter brokers. REX were building an impressive client list some years ago and the demand for charter was going through the roof. Sadly all the hard work done by the then Charter Manager was wasted as REX pilots began to leave in droves!
Since then REX Charter has bumped along, a shadow of it's former self, unrealised potential squandered.
Enter REXJET. They simply organise the client list and engage the most suitable third party operator to do the flying. The Westwinds aren't even in the equation. It's been done before, and so long as you can control the client, it can be done with a certain amount of success. Unless of course your clients decide to cut out the middleman!