Gouping of aliases into their own group

Question

I have a tool that manipulates two resources: r1 and r2. Each of which has its own click group, with get command inside:

import click

@click.group
def cli():
    pass

@cli.group
def r1():
    pass

@r1.command("get")
def r1_get():
    click.echo("r1.get")

@cli.group
def r2():
    pass

@r2.command("get")
def r2_get():
    click.echo("r2.get")

if __name__ == "__main__":
    from click.utils import get_os_args

    cli(get_os_args())

I can invoke commands:

$ tool r1 get
r1.get
$ tool r2 get    
r2.get

I'd used recipe from https://stackoverflow.com/a/47985653/38592 to create aliases:

aliases = dict(
    r1get='r1 get'.split(),
    r2get='r2 get'.split(),
)
@click.group(cls=ExpandAliasesGroup, aliases=aliases)
def cli():
    pass

This fills root group of my tool with aliases:

$ tool r1get
r1.get
$ tool r2get
r2.get

---

I want to enable following:

$ tool get r1
r1.get
$ tool get r2
r2.get

I'd tried something like this:

aliases = dict(
    r1='r1 get'.split(),
    r2='r2 get'.split(),
)

@cli.group(cls=ExpandAliasesGroup, aliases=aliases)
def get():
    pass

But this does not work, since r1 and r2 are outside of scope of the get group.

$ tool get r1
Error: No such command 'r1'.
$ tool get r2
Error: No such command 'r2'.

What should be proper way to group such aliases into its own get group?