Thanks for all the responses. These are very helpful.

[Laurent Le Meur: Note NewsML-G2 defines a property named <instanceOf>
specifically for this purpose ("thread" or "fixture" like "market
opening").]

[Misha: When using the NewsML-G2 Subject property to tie together News
Items about an event one would place an Event identifier in the
Subject property.]

We are using NewsML 1.2 right now, so we may not be able to make use
of the NewsML-G2 features. Though it appears that that may be a
standard way of creating the association between different stories of
a "thread". Also if all wires use this feature, it may make it easier
for news processing systems.

[Laurent Le Meur: Currently most wires use a slug term for this
purpose (ex. OLY2008)]

Could you please expand on that?

[Jayson Lorenzen: /NewsML/NewsItem/NewsManagement/AssociatedWith:
Create a document that identifies the thread and ties other documents
together...]

[Takahiro Fujiwara: /NewsML/NewsItem/NewsManagement/DerivedFrom: You
can describe details in FormalName attribute]

These are interesting suggestions.

We would ideally like to identify an element that is set by the wires
themselves or can be deduced on our end with a reasonable degree of
reliability. Using the AssociatedWith element and creating a "meta"
document would imply that this identifying document will be stored in
the news storage system.

Also it appears Reuters uses the
/NewsML/NewsItem/NewsComponent/NewsComponent/NewsLines/SlugLine
element to identify/set the
"thread" in NewsML.

thanks,
-Masood