Selctive protecting endpoint with Apache/mod_shib

[Marek Denis]

Dear users,

I was wondering whether there is a possibility to configure Apache in
a manner, where certain url is protected basing on some input a user
sends..or at least certain conditions?
I would like the users to always access one URL - say
https://host/auth/tokens but at the same time be able to choose from
many authn methods (apriori of course). These are: SAML2 based as well
as some internal ones, handled by underlying application (e.g.
login/password pairs). Is there any way to configure Apache and/or
mod_shib so it would not start federated-protocol dance always but
only under some circumstances - certain input sent by the user or a
HTTP variable present in the header?

Thanks a lot for your help.

--
Marek Denis