[exim] Can the Interface Option be Randomized

I have a need to split up messages internally on my server. I do not believe I
an use the remote_smtp option when I am all on the same server, so I am
trying to do this:

remote_smtp:
  driver = smtp
  interface = 1.2.3.4 : 1.2.3.5: 1.2.3.6 :1.2.3.7     
  hosts_randomize

and I know that hosts_randomize is not correct there.

Thoughts anyone?