[syslog-ng] can syslog-ng extract part of the hostname and make directory on the fly?

I have few hundreds of hosts, and say hosta has dns name groupa-hosta hostb has dns name groupbhostb hostc has dns name groupc.hostc ..etc..etc (note the first 6 characters defines the group) When a log comes in, can syslog-ng extracts the first 6 character from dns name, and drop the log file to the corresponding group? (So log from hostb will go under /log/groupb/groupahostb ) I cannot predefine the groups though, since i don't know how many groups will be there, the only thing i know is the first 6 character of the hostname will be the group name thanks