Subsidiaries vs. Head quarter ?

Subsidiaries vs. Head quarter ?

Hi, 
I am studying the use of Zoho CRM for our companies. We have 10 subsidiaries linked with the head quarter. I am not interresting in having one Zoho CRM account for each subsidiary. One commercial user can have accessed to customers and contacts from one or two subsidiaries. 
A customer, a contact or a prospect is handle toward one subsidiary. 

Can i use "Sector" and "Hierarchical sectors" to organize our companies ?

Thanks, 
Patrice