This is, I think, the complete list of Station Groups...
Bedford Stations, Bicester Nth/Vil, Birmingham Stns, Bootle Stations, Bradford Yk Stns, Cambridge Stations, Canterbury Stns, Catford Stations, Colchester Stns, Croydon Stations, Dorchester Stns, Dorking Stations, Edenbridge Stns, Enfield Chse/Twn, Falkirk Stations, Farnborough Stns, Folkestone Stns, Gainsborough, Glasgow Cen/Qst, Heathrow Rail, Helensburgh Stns, Hertford Est/Nth, Liverpool Stns, London Terminals, Maidstone Stns, Manchester Stns, Newark Stations, Penge East/West, Pontefract Stns, Portsmouth Stns, Reading Stations, Southend Cen/Vic, Thorne Nth/Sth, Tilbury Town/Riv, Tyndrum Stations, W Hampstead Stns, Wakefield Stns, Warrington Stns, Wigan Stations, Worcester Stns