Correlating values in Python Arrays

I have a vector called POSITION, with the following values:

• position = [40.51, 30.52, 30.31]

I have a vector called COORDINATES, with the following values:

• coordinates = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120]

Each index of the POSITION vector corresponds to another 4 of the coordinate vector. For example:

• position = 40.51 , 30.52, 30.31]

corresponds to:

• coordinates = [ 10, 20, 30, 40 , 50, 60, 70, 80, 90, 100, 110, 120]

I have the script below that, when detecting a value above 40.00 in the POSITION vector, assigns random values to the corresponding 4 positions in the COORDINATED array.

import random

posicao = [40.51, 30.52, 30.31]
coordenadas = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120]

for indice in range(0, len(posicao)):
    if posicao[indice]>40:
         for indice2 in range(indice*4, indice*4+4):
            coordenadas[indice2] = random.randrange(0,200) #gerar os aleatorios entre 0 e 200

print(coordenadas)

However, I wish instead of modifying the 4 values, just modify the last 2, for example:

• position = 40.51 , 30.52, 30.31]

Modify only:

• coordinates = [10, 20, 30, 40 , 50, 60, 70, 80, 90, 100, 110, 120]

How do I change this code to achieve this?

I am grateful to those who can help me. I think it's something easy, but I can not see the solution.