Process first 4 ingredients in a food processor until smooth, stopping to scrape down sides. With processor running, pour 1/4 cup oil through food chute in a slow stream; process until smooth.
Place tenderloins between 2 sheets of heavy-duty plastic wrap, and flatten to a 1/2- to 3/4-inch thickness, using a meat mallet or rolling pin. Spread rosemary mixture evenly over top of 2 tenderloins; top with remaining tenderloins, and tie together with kitchen string.
Rub remaining 1/4 cup oil over pork; sprinkle with salt and pepper.
Prepare a hot fire by piling charcoal on one side of grill, leaving other side empty. (For gas grills, light only one side.) Place food grate on grill. Arrange pork over unlit side.
Grill, covered with grill lid, 1 hour and 30 minutes or until a meat thermometer inserted into thickest portion registers 155°. Let stand 10 minutes or until thermometer registers 160°.