Set access control rule in EMQX Cloud

Hello everybody!
I have a topic named “/vehicle/{client_id}”. I want to allow only messages coming from client_id=x to be published to and received from topic “/vehicle/x”. I know that it is possible by specyifing two acl rules like this:

{allow, all, all, ["/vehicle/${clientid}"]}.
{deny, all}.

The problem is that EMQX cloud does not seem to allow users to modify the acl file.
Is there somehow a way to achieve this?

Thank you for your patience.

You can modify the file and restart, i mapp it in from a shared disk.

Could you please give me additional info on how can i do that?. I am not quite sure on how to “map” the acl file from a shared disk. Thanks.