Knowing JRiver, there is most likely many ways to do this.
I'm going to focus on the one that I know which is using REST web service calls.
Open Tools Then Options in menu.
Select Media Network from the left hand tree menu.
Turn on the Media Server.
Then click on the Open with web browser link under the MSWS (web service) menu
It should open up a page in your web browser with an address similar to
http://localhost:52199/MCWS/v1/This page contains the list of commands you can send JRiver using it's REST service.
There are many examples commands for you to try.
Notice the word localhost in the web address?
Your PC knows how to get the right address for the JRiver REST service using that special keyword.
The issue is you might want to send these commands from another machine on your network.
To make that happen, we need your current IP Address for your PC where JRiver installed.
The easiest way is use Windows Key + R, then type cmd in the box and hit Ok
type ipconfig in the command prompt and hit enter.
Your current IP address is listed there.
Mine is 192.168.1.127
replace the word localhost in the address bar with the IP address you looked up like the following.
http://192.168.1.127:52199/MCWS/v1/You should see the same information listed before when the web address was pointing to localhost.
I've read some of the examples on this page and I've picked one we can try together.
I found it under the "Perform a database search for files." example.
It teaches you how to build a URL to navigate to that will perform the desired action.
The following link will search for the database for "Journey Open Arms"
http://192.168.1.127:52199/MCWS/v1/Files/Search?Action=Play&Query=Journey Open Arms&ActiveFile=-1&Zone=-1&ZoneType=ID
Let's break it down.
http://192.168.1.127:52199/MCWS/v1/This part is the base URL for your server
http://192.168.1.127:52199/MCWS/v1/Files/SearchThe Files and Search part of the address is telling it what kind of actions to perform
http://192.168.1.127:52199/MCWS/v1/Files/Search?Action=Play&Query=Journey Open Arms&ActiveFile=-1&Zone=-1&ZoneType=ID
Everything that comes after the "?" symbol are parameters for the action.
Let's talk about the most important two in this case, Action & Query.
Action=Play plays the results instead of just listing them and Query=[whatever you want goes here] does the actual lookup.
If I wanted to search and play Journey songs, I would change it like so.
http://192.168.1.127:52199/MCWS/v1/Files/Search?Action=Play&Query=Journey&ActiveFile=-1&Zone=-1&ZoneType=IDIf I wanted to search and play songs from Journey Escape, I would change it like so.
http://192.168.1.127:52199/MCWS/v1/Files/Search?Action=Play&Query=Journey Escape&ActiveFile=-1&Zone=-1&ZoneType=ID
Change the values to stuff you know is in your collection and try it by pasting the address into your web browser. It should find the tracks and start playing them in JRiver.
You might need to tweak the queries so album tracks come back in the right playback order but the basics work.
I'm not familiar with Event Ghost but I'm sure there must a plugin or a native way to make REST service calls to the server.
All you need to do is build the right URL and then send it using whatever Event Ghost uses to make REST calls.
I found this posting that might interested since it looks close to what you need to do.
http://www.eventghost.org/forum/viewtopic.php?f=2&t=3226