DNAT possible with the string module?

["Udo Rader" <spamtrash2@vibe.ac>]

hi,

I would like to do the following thing:

2 daemons listening on different ports (lets say 1234 and 2345). 

The firewall then ideally takes all connects from clients to port 1234, 
looks for a "magic string" (using -m string) in the packages and based 
upon the (non)existance of the string finally decides, which daemon to 
forward the connect to.

... is there a chance for this to work?
... or any other ways to achieve this?

thanks for your work!!!

udo