Los reyes del Grial / Margarita Torres Sevilla, José Miguel Ortega del Río ; edición de María Robledano. (OCLC #878689024)
Only the first statement of responsibility is core in RDA, so we could have chosen to omit “edición de María Robledano”.
A statement of responsibility listing more than one person (such as “Margarita Torres Sevilla, José Miguel Ortega del Río”) is recorded as a single statement. There is an optional omission rule which says that if a statement includes more than three (!) people, you may omit some of them and record a summarized version, such as:
edited by Bob Smith, Jon Jones [and two others]
Both LC-PCC PS and NLA PS say to generally not omit names.
When recording relationships between people and resources (for example, via main or added entries in a MARC record), only the first creator (or someone used to create the AAP) is required; I chose to record the relationship for the second creator (in a 700) as well.