network setup question

[mp3sub]

Greetings All -

Few friends and I are working on a project such that they needs access to one of my machines in my network ('X' in the diagram below).

I have ASUS-68U router with merlin (380.59) installed. Please see the diagram below. My requirements are:

1. Computer X needs to be accessible to VPN clients
2. Computer X needs to have 2 ip address - one visible to VPN clients, one visible to internal computers (A, B, C)
3. Computer X should not be accessible to outside world (w/o VPN access)

Is this setup possible using ASUS Merlin alone? Do I need to buy any new network device? Your help is greatly appreciated.

+--------------------------------------------------------+
                     
             network accessible to VPN clients

                 +---------------------+
                 |                     |
                 |        X            |
                 |                     |
                 |   (ip address 1)    |
                 |                     |
                 |                     |
                 |                     |
+---------------------------------------------------------+
                 |                     |
                 |                     |
                 |    (ip address 2)   |
                 |                     |
                 |                     |
                 |                     |
                 +---------------------+
              internal network
              (not accessible to VPN clients)

    +---------+    +---------+    +---------+
    |         |    |         |    |         |
    |         |    |         |    |         |
    |  A      |    |   B     |    |   C     |
    |         |    |         |    |         |
    +---------+    +---------+    +---------+