  We study the orbital-dependent superconducting pairing in a five-orbital
t-J1-J2 model for iron pnictides. Depending on the orbital selectivity of
electron correlations and the orbital characters along the Fermi surface, the
superconducting gap in an A_{1g} pairing state may exhibit anisotropy. This
anisotropy varies with the degree of J1-J2 magnetic frustration. We have also
calculated the dynamical spin susceptibility in the superconducting state. The
frequency dependence of the susceptibility at the antiferromagnetic wavevector
(\pi,0) shows a resonance, whose width is enhanced by the orbital dependence of
the superconducting gap; when the latter is sufficiently strong, the resonance
peak may be split into two. We discuss the implications of our results on the
recent angle-resolved photoemission and neutron-scattering measurements in
several superconducting iron pnictides.
