How to run nested xargs commands?

I am trying to loop through all sites on a multisite network, and for each site, delete all subscriber users. I have tried this WP-CLI command:

wp site list --field=url | xargs -n 1 -I ^ wp user list --url=^ --role=subscriber --field=ID | xargs -n 2 -I % ^ wp user delete % --url=^ --reassign=4

I can’t find a way to pass the ^ value to the second xargs command. Anyone?

xargs is unnecessary, something similar to this will do the job without any piping or xargs:

sites=$(wp site list --field=url)
for site in $sites
do
  users=$(wp user list --url="$site" --role=subscriber)
  for user in $users
  do
    wp user delete $user --url="$site" --reassign=4
  end
end