// loop over group field
if (have_rows('testimonials')) {
// always true
while (have_rows('testimonials')) {
// always happens once
the_row();
// loop over the repeater
if (have_rows('testimonial_repeat')) {
while (have_rows('testimonial_repeat')) {
the_row();
// get repeater sub field
$post_object = get_sub_field('testimonial_object');
} // end while repeater has rows
} // end if repeater has rows
} // end while group field has rows
} // end if group field has rows