HAProxy community

On the fly let'sencrypt for unknow domain

I search a way to use haproxy, not only for renewal, but for passing request to certbot, in case of lack of ssl for a not know domain that point to the public IP of the Haproxy .
I have lot of domain, and want to pass them to https .
Is there a way to do a rules if haproxy lack of the cert with SNI, to go in a dedicated backend for generate it ?

I’m not aware this is possible, no.