Is it possible to integrate multiple instances of DNG?

The simple answer is "yes". You can stand up essentially as many instances of DNG or RQM or RTC as you like and then link them. They can all use the same JTS (although at some point you may want to spread the wealth of back-end communication and core logic between multiple JTS instances as well) or stand them up completely separately. You do this through the Friend (Outgoing) and Consumer (Incoming) references and then you can specify link types that will interact between those connections.

While I do have multiple RTC instances and have only explored implementing an extended DNG and RQM implementation using the same structure I think it would be great to get feedback here from the IBM architects that implemented the managed services and/or the Jazz.net Sandbox environments. They are definitely extending the functionality through Friend relationships and have really pushed the tools quite a bit.

I hope that is of some small amount of help.

Regards,

-michael