I am a Senior Network Engineer with more than 6 years of experience with project design and implementation with CISCO Devices. I am CCNA Voice, CCNP R&S and CCIEw R&S certified. In this case you need to implement route policy and nat failover for 3 ISP links. This is a very common topology that I have implemented in a lot of clients. I have done the same setup here at my office. If you want to finish this project soon please contact me.
Kind Regards,
Ibra Ramku
Sr. Network Engineer
CCNA Voice, CCNP R&S, CCIEw R&S