You can definitely script this if the problem is consistent enough to write logic for. But you'll have to be familliar with at least one of the supported scripting languages and you will not be able to rely on your kiwi generated statistics because they will be wrong.
In your example, if this:
02-06-2013 13:01:35 Local0.Info 10.x.x.x Feb 6 13:01:37 pf: 10.x.x.xx.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:xx:56:9d:53:fc, length 313, xid 0xf7d8ecbb, secs 3328, Flags[bcast]
is the problem and that should be one syslog message but comes in as two... Even if it's not consistent, you have something to script here...
You capture every message that comes through, but you store the message and stop processing it. If the next message from that device does not match the pattern ##-##-#### ##:##:## then you append it to the message already stored and process both messages as if they were one in the same.