There are different ways that an organisation can take part in an FP7 Project. The majority of organisations participate in projects as Consortium partners, or Beneficiaries as they are now known.
Another way an organisation can take part in FP7 Projects is as a Third Party. Subcontracting is a type of Third Party participation; however it is subject to specific rules.

The Finance Helpdesk has published a leaflet to explain these specific rules. The leafletcan be downloaded from there site, members login required.