A vSAN Stretched Cluster requires both compute placement control and storage placement control. To place virtual machines in the appropriate site, the administrator must create VM/Host groups for the two sites. This allows DRS to understand which hosts belong to the preferred site and which hosts belong to the secondary site, and it allows VM-to-host affinity rules to be created for initial and ongoing placement. The administrator must also create a storage policy for each site or site placement requirement. vSAN stretched-cluster storage policies control site disaster tolerance and data locality, including whether objects are mirrored across sites or kept on the preferred or secondary site. VM folders do not control runtime or storage placement. A VM/Host group "across the two sites" is not correct because site separation must be explicitly modeled. Simply placing a VM into a DRS group is not enough unless the site groups and policies already exist. Reference topics: vSAN Stretched Cluster Design Considerations, DRS Host Groups, VM Groups, VM-Host Rules, vSAN Storage Policy Site Locality.

Windows Server Failover Cluster shared disks require coordinated access to shared block storage.
vSAN supports Windows Server Failover Clusters by providing SCSI-3 Persistent Reservation support at the virtual disk level, which allows cluster nodes to arbitrate access to a shared disk resource. One supported approach is to use the vSAN iSCSI Target Service, which presents vSAN-backed LUNs to initiators and can be used for clustered workloads that require shared block access. Another supported approach is to configure a shared virtual disk using a VMware Paravirtual SCSI controller with physical bus sharing. Physical bus sharing allows multiple VMs to access the same shared virtual disk in a WSFC configuration where supported. Raw Device Mapping is not the vSAN ESA-native solution for this requirement. NFS v4.1 is a file datastore protocol, not a WSFC shared block disk mechanism.
"LSI SCSI controller per disk" does not satisfy the required shared-disk bus sharing configuration.
Reference topics: vSAN Support for Windows Server Failover Clusters, SCSI-3 Persistent Reservations, vSAN iSCSI Target Service, Shared VMDK Configuration.

Assigning different vSAN Storage Policies to each file share during creation satisfies the requirement because vSAN File Service allows each file share to be created with its own storage policy. The Create File Share workflow includes a Storage Policy selection, which controls how the file share's underlying vSAN objects are protected and placed. This is the correct mechanism when each department requires distinct protection levels or placement rules. IP pools and file server bindings provide network endpoint capacity and service placement, but they do not define the protection level of file share data. Creating separate File Service clusters per department is unnecessary and operationally inefficient because file shares can be differentiated by policy within the same File Service deployment. vSphere Compute Policies influence compute placement, not vSAN object protection or file-share resilience. Therefore, the department-specific requirement is fulfilled directly by assigning the appropriate vSAN Storage Policy to each file share at creation time. Reference topics: vSAN File Service, Create File Share, Storage Policy, Placement and Protection Rules.