Apache conditional configuration

Question

Is it possible to dynamically include/exclude blocks somehow using env variables or the like? Something in the lines of

<LocationMatch ...>
  SetEnvIf X-Requested-With XmlHttpRequest xhr
  <If xhr>
    SSLVerifyClient none
  </If>
  <If !xhr>
    SSLVerifyClient optional
  </If>
</LocationMatch>

Answer 1

You mean like this?