[Ifeffit] Sorbed complex in Atoms

Dear All, I am relatively new to Ifeffit and Artemis. I am trying to find a way to create four-shell model of an outer-sphere complex in Atoms or some other way readable by Atoms. I have no idea about the geometry, space group but some rough guess of bond-distances. The model to test against the EXAFS data is: Ni is the central atom Ni-O first shell Ni-Ni second shell Ni-Ti third shell Ni-Si fourth shell The model aims to test the adsorption of Ni on the surface of Ti-containing silicate mineral. Could you please help. Thanks.