Disable challenge on some replicas

i want to use traefik with acme and store all certs on file. I want to use multiple traefik instances mounting on every instance the same file storage, but with only one traefik instance dedicated to the certificate requests to acme (by dns-01 challenge). By using this trick i think to be able to share all certs to all instances, but i've noticed that i can't disable traefik from trying to issue the cert and that if i try to disable 2 instances unsetting some properties they can't read the new certs... why we are forced to use the kv? there are many other methods to be sure that there aren't parallel write on file... If i must use it, can i use redis to store ONLY the certificates?