Can override monitor for group

Hi,   We created a unix linux shell command  2 state monitor that we setup to run a shell command.    We also created a group that contains 2 linux machines that we want to enable this monitor on.   After creating the monitor, we tried to override the monitor and enable just for this group.

When we do this, we can see any of the custom groups that we have defined listed.  None of them.   It seems like this is not right.

What would cause non of our custom groups to show up when overriding a monitor for a group?

Thanks Lance