Like pension plans and gold watches for retirement with a company, sponsored education is a rare thing.
I know two people who did this but it required a huge commitment - in each case the employer and university each wanted their pound of flesh essentially requiring the candidates to double up their schedules. That meant full time 9-5 hours at the company followed up with 6pm - 11pm weekday hours and 8 hour days over the weekends at the university to meet the full time academic requirements. Add into this mix, the need for flexibility to take academic classes for the first 1 - 2 years and you can see how daunting it can be.
For both of the people who I knew who succeeded in this endevor, they were absolutely driven and willing to keep themselves very tightly focused. Bill told me that he was able to become astonishingly productive because there was no other way to make it. He also said that because much of his work was after hours he could use typically shared analytical and preparative instrumentation at his leisure making it possible for him to run twice as many experiments as his colleagues. He finished a productive chemistry PhD in 4 years which was about a year faster than the department average.
You can do it- just make sure you are fully aware of the competing interests that could give you headaches and be willing to personally meet the challenge.