How can I make weak point's?

Questions & Answers
1

public Gameobject shield 1
public Gameobject shield 2
public Gameobject shield 3

//How would I make 3 separate game objects be required to be destroyed first before you can attack a fourth GameObject? If any one of them is still active, you would be unable to deal any damage to the fourth object, even if one of the first three objects is still active.

void OnTriggerEnter(Collider col)
{
if (shield1 || shield2 || shield3 == false)
{
curHP -= 15; //will decrease health
}
else
{
curHP -= 0; //will not decrease health
}
}

2

If one of the gameObjects in the array exist and is active, then, the current HP will remain the same. If all the objects have been destroyed (or as disabled), the health will decrease.

public GameObject[] Shields;

void OnTriggerEnter(Collider col)
{
    for( int i = 0 ; i < Shields.Length ; ++i )
    {
        if( Shields _!= null && Shields*.activeSelf )*_

return ;
}
curHP -= 15;
}