Pursuant to regulations prescribed by the President, and to the extent consistent with the other provisions of this chapter, where funds are provided for a single project by more than one Federal agency to any agency or organization assisted under this chapter, the Federal agency principally involved may be designated to act for all in administering the funds provided. In such cases, a single non-Federal share requirement may be established according to the proportion of funds advanced by each Federal agency, and any such agency may waive any technical grant or contract requirement (as defined by such regulations) which is inconsistent with the similar requirements of the administering agency or which the administering agency does not impose.