problems with independent node set ups instead of vhosts?

I want to split up my application in two parts:

1. Public accessable, does registration, login, resetting. (security.example.org)
2. Private accessable, provides internal api requires authentication (app.example.org)

I would now like to know if it would be a good idea to seperate them into two independent node set ups instead of using connect.vhosts.

The benefit would be that we can develope both parts independently and they also should work quite independent with the exception that the app part requires the security one.

I just have following problems about this idea:

• port overlapping when running on one host
• cross-domain set up for client application
• other incompabilities?

Does somebody got already experience about using multiple node projects side-by-side?

If yes what could other possible issues can be?

Best Regards