I need some asssistance - i have been asked to compile a job description for the following role:

A person to liaise between procurement department, accounts payable department and end users. To improve the relationships between the departments and end users. To ensure corporate governances, policies and procedures are followed. to assist with training and educating all parties involved with regards to the benefits of having purchase orders in place, as well as the complete procure to pay cycle. ensuring that when ap have queries they are resolved quickly, and vice versa. Improving the processes. Basically act as a mediator and facilatator between all the departments and parties involved. also ensuring budgets are adhered to

Has anybody done any job descriptions for something like this. its a complete new role in our organization, which is quite a large organization. person would have to have good knowledge about both AP procedures and procurement procedures

if anyone can help it would be appreciated as i am a bit stuck