Multiple subdir multisite installations under same domain

Hi,

I have a slightly unique situation here and I'm trying to find a way to implement this with EasyEngine.
I have 3 different multisite installations (subdir) under a single domain like this:

domain.com/mu1/site1
domain.com/mu1/site2
domain.com/mu2/site1
domain.com/mu2/site2
domain.com/mu3/site1
domain.com/mu2/site2
etc.

I can make mu1 work if I change my common/wpfc.conf to

location / {
  try_files $uri $uri/ /mu1/index.php?$args;
}

and

location ~ \.php$ {
  try_files $uri /mu1/index.php;
[...]

but that as far as I can get. How can I make the other 2 work?

I've also edited common/wpsubdir.conf and added:

  rewrite ^/mu1(/[^/]+)?(/wp-.*) /mu1$2 last;
  rewrite ^/mu1(/[^/]+)?(/.*\.php)$ /mu1$2 last;

however, adding mu2 & mu3 there shouldn't be an issue. I'm more concerned about the wpfc.conf part of the configuration.

If anybody can share a tip, I'd be grateful!

Thanks