How to code conditional copy

[Morgan Ives]

I am trying to code conditional copies based upon the existance of
 a file on each client.   For example if:

  /.XXX exists then
copy::
 /local/masterfiles/.example.xxx dest=/usr/local/bin/example mode=600

 /.YYY exists then
copy::
 /local/masterfiles/.example.yyy dest=/usr/local/bin/example mode=600

I am thinking this can be done with filters but I am having trouble with the syntax.
Does anyone have a quick example of this?
 
              Morgan