516605 Repricing program for amazon US and JP

I'm selling items through [login to view URL] and [login to view URL], and looking for a repricing tool for both of them. The repricing tool MUST work with [login to view URL] as well as amazon.com. Currently I have around 5,000 kinds of items for sale, and the total number is still increasing. So it is supposed to handle 10,000 inventories at least. Maintaining the lowest prices when there is any competition in same condition, and making items back to default prices when there is no competition. This is the main reason I need a tool. If you are familiar with amazon sites, you will understand what I mean. I will give you further information if anyone is interested in my project. Thank you. Park