How to change Packets TTL (Time to Live) value in firewall?

Is there a feature in Sophos Firewall to change TTL value of packets so that the authorized users in my network cannot share internet access by creating their personal WiFi Hotspot to connect unauthorized users to access the internet through my network?

Please let me know and help me on this matter. If there is no such feature in Sophos Firewall then how can we recommend the Sophos to add this feature in their firewall as soon as possible.

Thank you so much