Hi there,
I read your project and it is quite interesting. In fact, I've built very similar projects before, please, take a couple minutes to enter my profile, there you will find in my portfolio a project named "MT4 Trade Copier", which contains pretty much the same features you request in your project. I am IT engineer and I work exclusively with Financial Market solutions including, MT4-5, Easylanguage, Metastock, custom Broker API connections (Interactive Brokers, Rithmic, etc), Reuters Xenith, etc, etc.
This is a stable solution, which uses NamedPipes and native Win32 functions as communication protocol between the MT4 instances and the TradeCopierServer (C# app which receives and handles all MT4 connections and messages). It allows you to work in Automatic mode where you select a Master account so it can read the trades from that account and replicate them to the rest of the MT4 instances registered, or in Manual mode, where you manually send market orders to all registered instances.
It will work with any Broker as soon as they use MT4 as trading platform. It is also of my knowledge that the symbol name may be different from one broker to another, so for this case, it is easy to solve, it is a matter of creating a Dictionary with all synonyms of the available symbols and registering the symbols used by each Broker...
...I was writing more details on my proposal but I have a limited number of characters. If you have any question just send a message.
Regards,
John