Context: The recent discovery of a group of trans-neptunian objects (TNOs) in a narrow region of the orbital parameter space and with surfaces composed of almost pure water ice, being 2003 EL{61} its largest member, promises new and interesting results about the formation and evolution of the TNb and the outer Solar System. Aims: The aim of this paper is to obtain information of the surface properties of two members of this group ((24835) 1995 SM{55}, (120178) 2003 OP{32}) and three potential members (2003 UZ{117}, (120347) 2004 SB{60} and 2005 UQ{513}) and to use that in order to confirm or reject their association. Methods: We obtained visible spectra of five TNOs using the 3.58 m Telescopio Nazionale Galileo at the “Roque de los Muchachos Observatory” (La Palma, Spain). Results: The spectra of the five TNOs are featureless within the uncertainties and with colors from slightly blue to red (-2 < S' < 18%/0.1 μm). No signatures of any absorption are found. Conclusions: We confirm the association of 1995 SM{55} and 2003 OP{32} with the group of 2003 EL{61} as their spectra are almost identical to that of 2003 EL{61}. Only one of the three candidates, 2003 UZ{117}, can be considered as a possible member of the EL{61}-group, as its visible spectrum is compatible with a spectrum of a surface composed of almost pure water ice and no complex organics. The other two, 2004 SB{60} and 2005 UQ{513} are red and must be considered as interlopers.