How to `show` an outline at each level 1 heading for all its child headings?

[Andrew]

#import "@preview/suboutline:0.3.0": suboutline
#set heading(numbering: "1.1.")
#show heading.where(level: 1): it => it + suboutline()

= Heading
== Heading
#lorem(20)

=== Heading
#lorem(30)

== Heading
#lorem(10)

= Heading 2
== Heading
#lorem(20)

=== Heading
#lorem(30)

== Heading
#lorem(10)