This should do it:
app.changeGrepPreferences.appliedCharacterStyle = app.activeDocument.characterStyleGroups.item("group name").characterStyles.item("style name");
app.changeGrepPreferences.appliedCharacterStyle = app.documents.characterStyleGroups.item("GroupName").characterStyles.item("StyleName");
Beat ya to it!
Yeah! About a minute.
That seems to have fixed it.
You are all too quick!
We recently bought a pagination system that is based on InDesign, but does not support style groups. Makes for a long, flat list of paragraph styles. We will try to persuade the developers to get up to date.