... I even tried separating this out into three entries, each with a single Match[section]. By changing the order I discovered that it is always the last entry that is recognised - the first two are ignored.
This approach should work. From your error description I guess that you have really copied the section three times and just changed the section ids. But you also need to change the name of this override match (the [pagelayout_groups]). Otherwise the last entry will overwrite any preceding entries with the same name.
