Need "-keepfor" option with consistency groups

Hello,

I have a dozen VNX snaps to create and have expire after a period of time. I would like to create a consistency group for this so I can just send one command to the array instead of twelve. According to the CLI reference manual, the "-keepfor" option only exists on the "snap -create" command but not on the "snap -group -create" command. Isn't there a way to set the expiration time on a CG, or all of the luns within a CG, without having to run a modify command at a later time?

Thanks.