Yes, you are able to keep the InstaShow VS20 Host cut-off from the Internet to prevent unauthorized access. As long as the InstaShow VS20 Host and the BYOM devices are connected to the same Intranet network, the BYOM device will be able to access the InstaShow VS20 Host and any video conferencing devices connected to it.
Use an indirect connection to set the InstaSHow VS20 Host and any devices in the same Intranet. You can then use your organization’s existing authentication process to let the employee’s device (e.g., laptop) go online at the same time.
BYOM Indirect Connection to the InstaShow VS20 Host