[exim] Authenticators chaining

Good day.

Today I was in touch of configuring two different smarthosts for
a node, each smarthost requires authentication, and I was very
surprised by the fact that Exim does not allow chaining of
authenticators (as routers). Each authenticator must have unique
"public name", denoting its mechanism (CRAM-MD5, PLAIN, etc).
That's why I have to pack code lines for different smarthosts
into one authenticator. It looks messy. Better solution, IMHO,
would be to write two authenticators in chain, each with

client_condition = ${if eqi{$host}{...}}

Is there some reason to prevent chaining of authenticators
with the same public name, or is it just a design flaw?
--
Eugene Berdnikov