Entities that are not clusters organisations or cluster networks (as defined by the Call for proposals) are eligible to be part of a consortium. Allowable entities include academic institutions, non-profits, commercial ventures, government bodies, and small businesses.
For other eligibility criteria, see https://ec.europa.eu/info/funding-tenders/opportunities/docs/2021-2027/smp/wp-call/2024/call-fiche_smp-cosme-2024-cluster_en.pdf.