CODING with 62 Modifier

My Vascular Surgeon performed an EVAR of AAA with a a Co-surgeon and an Interventional Radiologist which one of these doctors other than the Vascular Surgeon is allowed to append "62" modifier on the CPT Code 34803? I am having a real problem with the Interventional Radiolist, he keeps calling and telling me to append the modifier on my Vascular surgeons claim when he did not perform surgery. I believe if anyone should have the 62 modifier it's the Co-Surgeon. Please advise if you can.