Duplicate GUID on Different sites

I have setup a merge replication and many push subscriptions. The issue i am facing right now is the generation of same GUID on more than one sites when inserting a record. this thing causes conflicts at the time of synchronization and to resolve them record from one site is deleted. This thing is happening frequently please help me in this situation.
Please note that the GUID column always takes its default value which is NewSequentialID. I am badly stuck please help me as soon as possible
Regards
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I didn't get your question but check the following links may help you...
http://www.replicationanswers.com/Merge.asp
http://msdn.microsoft.com/en-us/library/ms151789.aspx

Let me clear the situation some more.

I have following setup

ACE_CMSACE_CMS (Distributer + Publisher)
LHRLHRDB (Subscriber)
ACEGRWCMS_GRW (Subscriber)

there are other subscribers but i haven't allowed any data to be entered on them as i have having problems with first two (as i have told in first post)

data is being directly entered on publisher database also on both subscribers
now in a table at LHRLHRDB 2 records were entered and merged to publisher
in the same table at ACEGRWCMS_GRW 2 records were entered but when i tried to merge the data 2 primary key conflicts were occured and i had to delete these records from one site.

checked the GUIDs they were exactly the same. i am not inserting these keys using my queries but it always takes the default value which is newsequentialid().

About IPs they are same on both sites but they are provided by my ISP and i have requested to change IP on one site. But if IP is not involved in generating GUIDs then please figure my problem out and let me know how can i resolve it