Short answer, Yes.
As of the latest release for the LTE Cat 1 (1008) the XBee Cellular has support for incoming connections using TCP and SSL. However, out of the box with a typical IoT SIM you won't be able to do it as it does require a static address for at least one of the XBee Cellulars. It will work best if you have a static address for both, so that either modem can initiate a connection to the other.
You'll want to determine the port that you want communications to occur and set the following settings:
- Set C0 (Incoming Port) on the XBees which will accept connections
- Set DE to match that port on the XBees which will initiate.
- Set DL to the address of the _other_ XBee on each XBee which will initiate.
That should be all you need for base configuration.
Regarding the ELIZA server, there's nothing special that was done to create that for the XBee Cellular. It will work the same if you use a tool like netcat to connect as it does for the XBee.
Setting up a server is probably beyond the scope of answering this question, but any socket server example on the Internet for any language that you like should serve. The example server was written in Python and here is a tutorial from the top of a search: http://www.binarytides.com/python-socket-programming-tutorial/.