SCNARIO AND FI TREATMENT

I have scenario here that, if we request some material for our 4 offices which are attached to one plant how i can differentiate the qty and how we can come to know that where this material has received and it value too and FI treatment and when invoice recieved what will be the treatment.

As per my understanding while purchasing we have to give plant for which plant we are going to purchase and when we do GR then we are going to give the location mean office location where we are going to received the material hence in the same way we can see its value and qty but value will be valuated at plant level, if anything else pls inform to me and if u can elaborate about FI in this scenario I will appreciate it.

Regards