I have discovered that their aunt, Marcela Torres Nicolas, attended the funeral of their mother, Concepcion Torres Nicolas. Marcela is simply described as "sister, widow of Roig". This would mean that her children would be "Roig y Torres".
I then found another link: 1913 June 04 - La Vanguardia - notice of ill health:
Found seriously ill, having had 'per diem', the distinguished lady Mrs Marcela Torres [Nicolas], widow of Roig, mother of ex-mayor and secretary of the Union of Wine Exporters, Mr Rafael Roig Torres. We wish for the prompt restoration of the sick.
(Dr?) Rafael Roig Torres appears to have led a very busy life... editor of Crónica Científica between 1878 and 1892, started the magazines "American Wine" and "Diseases of the Vine", he wrote many papers and books, was deputy mayor of Barcelona, and also appears to have been an artist/architect - between 1906 and 1912, constructing a noucentist and modernist building (Auditori can Roig y Torres) at Santa Coloma de Gramenet, a suburb of Barcelona - which stands out in a photo of the small suburb...
The house was passed down to his son, Dr Rafael Roig Ortenbach, who, after the death of his father's cousin, Modesto Texidor Torres, traded in materials for artists from Rambla Catalunya, 89, under the name "Sucesor de M. Texidor".