Designing Issue (dire straits)

Let me try an explain my problem to you...

I have to implement an EXE server. Client design is already designed (not my part). Client implements a sink interface (just for info).
I cannot use ATL due to speed issues.
Also I do not want to make use of singleton objects. (some constraints).

I have a single serial port, through which multiple clients(com), want to send and receive data. There will be single server associated with the serial port, which will handle sending and retrieving of data through the serial port.

The server will be started explicitly during boot up (since it is an EXE).

Each one of these clients, when they start, will call CoCreateInstance to create an instance of a class in the server's process space. The implementation of this class is supported in the server. These instances in the server's process space act as entry point for the clients to talk to the server.

My problem:
1) how do these instances tell the server, that OK i am created.

2) Is there anyway in COM to hook onto a running server?

Thanx for your help
Amit