A possible workaround is to use
org.hippoecm.hst.configuration.hosting.Mount#getMountProperties() after setting a mount property on each hst:root mount.
@hst:mountcmsbaseurl = "http://cms.example.com/ on an
hst:root mount under a vhost.
HstRequestContext#getResolvedMount().getMount(), find the root mount upward.
Mount#getMountProperties().get("cmsbaseurl"), which will return your configuration.
So, your code may depend on hst host / mount configurations. Even if you should set the properties on each
hst:root mount in every vhost, but that should be doable.