How to include the sub-blocks layout from the top layout automatically

My top schematic has several blocks. I generated the layout of the each block separately, and made those layout to be in good arrangement.

Then I generated the top schematic layout from the top schematic. I thought that from the top layout, it would automatically include these blocks layout I generated before.

However, in the top layout, it re-generated each blocks' layout, and those layout of those blocks are not the one I generated, the devices of the layout are randomly arranged.

In summary, I would like to generate the top layout from the top schematic, and the top layout should automatically use my previously generated block layouts with good design. How can I do that?

Thanks,
Shawn