Thanks for the reply.

If I am getting it right that you are referring to the order that the Wii Remotes take in the list while the application initializes, that's not something I can use, because the numbers of Wii Remotes connected doesn't have to the same always.
Here I need to find an invariant parameter that has unique value for each Wii Remote. So far I tried to identify Wii Remotes through the HID interface, but none of the following functions gave me something I could hook on:
HidD_GetManufacturerString - "UnKnownh"
HidD_GetPhysicalDescriptor - ""
HidD_GetProductString - "UnKnown2 Optical Mouse"
HidD_GetSerialNumberString - "UnKnownh"
HidD_GetAttributes - VID, PID, VersionNumber that are apparently same for many Wii Remotes
For now it remained a mystery to me how to obtain even the device address.
So, dead end for now. :|