Multiple WIP and timesheet integration

Hi,
I have created an Item and its BOM( three raw material items) for production order.
the item is created in 3 different floors where each raw material is used in those 3 different floors. 1st floor consumes 1 raw material to make something and transfer it to 2nd floor to further process it and then finally 3rd floor generates the finished product and sends it to finished goods warehouse.
How can I make 3 WIP for production order like this. The purpose is to track how much raw material is consumed in each floor to make the sub assembly item until it gets finished. Also, is there any way to link timesheet of production order with in/out of subassembly items from WIP. In this way the original time required for a certain operation can be automatically calculated instead of production user manually entering which he/she can obviously fake.

i have this situation also i need multi WIP warehouses to keep track of raw materials, in the diferent areas where we manufacture, right now this is hard coded to 1 WIP warehouse only, which is the best approach to modifiy this?,

Thank you!!!