How do i create a material that only shows a certain part of a texture?

Hello, i have a texture and i want my material to only use a part of that texture, say, from UV 0.5, 0.5f to 0.7f, 0.7f, but it has to be dynamic, because it can have different values at runtime. How do i accomplish this? I tried using the TextureCropping node like this:

But it’s not giving me what i want.