Insert object at index, when two objects collide

I have two arrays: one for projectiles, and one for targets.

Every target and every projectile has tag, and a tag with color (source code I took from Ray Wanderlich).

In my small game, when a projectile collides with a target I compare their tags, if the tags are the same I delete the projectile and target, but if they are not I want to insert projectile at the position of the target (with which the projectile collided) and make the other targets shift right or left.

Some code:

NSMutableArray *projectilesToDelete = [[NSMutableArray alloc] init];
CCSprite * projectile;
for (projectile in _projectilesArray)
{
    CGRect projectileRect = [projectile boundingBox];

    NSMutableArray *targetsToDelete = [[NSMutableArray alloc] init];
    CCSprite * target;
    for (target in _targetsArray)
    {
        CGRect targetRect = [target boundingBox];

        if (CGRectIntersectsRect(projectileRect, targetRect))
        {
            if([target tag]==[projectile tag])
            {
                [targetsToDelete addObject:target];
            }

            if([target tag]!=[projectile tag]) /* <-- _HERE IS MY PROBLEM_ */
            {
                NSLog(@"-");
                [targetsToDelete addObject:projectile];
            }
        }
    }

    for (CCSprite *target in targetsToDelete)
    {
        [_targetsArray removeObject:target];
        [self removeChild:target cleanup:YES];
    }

    if (targetsToDelete.count > 0)
    {
        [projectilesToDelete addObject:projectile];
    }
}

for (CCSprite *projectile in projectilesToDelete)
{
    [_projectilesArray removeObject:projectile];
    [self removeChild:projectile cleanup:YES];
}