Complex layout (content separation)

Hi, guys. Have question. I need to make a separation between the content in aside, main, hero and other sections. I have complex layout like this https://monosnap.com/file/E9pLQJ9IV3v81SaGt5Tvx5h66gtfor In documentation 15/content/modular we have a collection of modules of current page

content:
    items: '@self.modular'
    order:
        by: default
        dir: asc
        custom:
            - _showcase
            - _highlights
            - _callout
            - _features

So I decided to create several collections for each section of the layout. Like here https://monosnap.com/file/vAJQ9gcq02eN89YhN8ordKvF6Vs2dh The problem is that "@self.modular" rule take all modules of the current page. And I need only specific module or array of specific modules. How can I do that?