Memorandum: Requirements for Agents and Sponsors Filing as Petitioners for the O and P Visa Classifications [open pdf - 495KB]
"This memorandum clarifies the standards for adjudicating 0 and P petitions filed by a petitioner acting as a U.S. agent for a beneficiary or beneficiaries who will be working for more than one employer within the same lime period. This guidance applies only to 0 and P petitions where the petitioner is filing on behalf of multiple employers. This memorandum also reaffirms the definition of a U.S. sponsoring organization for the P Visa Classification."
HQ 1016.2.18 : HQ7016.2.19
U.S. Citizenship and Immigration Services: http://www.uscis.gov/