hi Edmund,
where exactly do you want this value to be set?
a) as a single value in each individual group 2?
you need to move the subreport to its own group header 2 section, above the existing group header 2 section. i.e. insert a new group header section, move the subreport to that new section, and then move that new section up so it is group header 2 A.
then you can move your shared variable formula to group header 2 B where the other existing fields are. you can also underlay group header 2A with group header 2B.
b) as a single value across an individual group1?
otherwise, if you're trying to get one consistent value from the subreport across a group 1, then the subreport must be on the group 1 level. otherwise that shared variable is not going to be consistent. moving that subreport up to the group 1 level has its own implications though as the record selection / linking may not match the group 1 level.
-jamie