I have example Post 1(id-1), 2(id-2), 3(id-3), 4(id-4), 5(id-5), 6(id-6), 7(id-7), 8(id-8) ,9(id-9)... with same catergory.

When in post 9, i need show related post 8, 7, 6

When in post 8, i need show related post 7, 6, 5

...

When in post 3, i need show related post 2, 1

When in post 2, i need show related post 1

When in post 1, don't show related post.

How can i do like this?

Thanks for your help