how identity some part of text in richTextBox

Question

Hi all,

I want to identity some part of text in richTextBox in this way that I would like link this selected part of text with some ID. These parts will be text visualization of some objects (so I need a key to identity this object) and I would like to know which of them are modified by user to start some action, e.g. start some wizard. Rest part of text can be freely modified (add, delete text) and also my 'text object' order can be freely changed e.g. by using copy and paste. I think that is also important that these part of text can look identical, while indeed they can refers to seperate objects.
Is it possible??

Thanks in advance for any help and suggestions,
Grek.