[exim] Rejecting RunTogetherSubjects spam

I've been digging into the syntax, but I'm at a loss of how to reject long subject lines lacking any
spaces?

I'm wanting to reject subject text strings over 24 char without a space.

This would reject longer subject lines.. but not what I want.
condition = ${if >{${strlen:$h_subject:}}{24}}

Might be I can't do this from within exim?

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Karl Schmidt                                  EMail Karl@???
Transtronics, Inc.                              WEB http://xtronics.com
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If one rejects laissez faire on account of mans fallibility and moral weakness,
one must for the same reason also reject every kind of government action.
Ludwig von Mises

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