Hi Planck,
You can refer to https://support.huawei.com/hedex/hdx.do?docid=EDOC1100122846&id=EN-US_TASK_0178939441&lang=en
This uses the same SSL VPN gateway and group objects and users to differentiate between departments.
After this configuration is done you can continue to configure service authorization.
Network extension service: Configure security policies, PBR policies, bandwidth policies, quota control policies, proxy policies, and audit policies that reference the user and user group objects.
Web proxy, file sharing, and port forwarding services: Reference the user and user group objects in the role module of the SSL VPN.
Please let me know if this helps.