Yes. There must be at least three legal entities established in different EU Member States or Associated Countries (the countries concerned are listed in section 3 of the Guide for Applicants). The entities must be independent of each other. A higher number may be specified on a call-by-call basis: check the call fiche. The size, scope and internal organisation of Integrated Infrastructure Initiative (I3) projects can vary from research theme to research theme and from infrastructure type to infrastructure type.