How can I extract from a heap dump instances allocated from a single thread?

Question

I have an application with degrading performance. I have analyzed its behavior using Java VisualVM. I detected a group of threads in a pool that increase their allocated bytes on each execution. So, I know where the problem is, however I can't find the root of the problem by looking at the code. I would like to look at the objects that these threads are accumulating. Is there a way to do this? I did a heap dump, but I can't find a way to get only the instances that represent the memory allocated by these threads.