Many-to-One integration between NAV R2 and CRM 4.0

Stark

Hi,
Our client has four companies in NAV:
- Company 1
- Company 2
- Company 3
- Company 4

and one Organization with four Business Units in CRM:
Organization 1
- BU 1
- BU 2
- BU 3
- BU 4

Now, they want to setup integration using R2 Connector.
Is it poosible to integrate each NAV Company with same CRM Organization but different BU?
Like that:
NAV Company 1 <-> Organization 1.BU 1
NAV Company 2 <-> Organization 1.BU 2
NAV Company 3 <-> Organization 1.BU 3
NAV Company 4 <-> Organization 1.BU 4

They have CRM professional license and cannot create several CRM Organization.

Thanks.