Resolution:
Steps to add multiple users/ roles to the domain without manually doing it via administrator:
1. Use the ExportDomainSecurity.exe (Location: C:\tibco\tra\5.2\bin) to export the required roles/ users/ associations to the xml file (for e.g. export.xml).
2. To add new users to the domain:
a. Don’t just add new users to the file as you need to remove all the users present in the file first, else if you try to add a duplicate user it will throw an error when you run importDomainSecurity command.
b. After removing all the old users / associations add the new users. For e.g. I am adding only one new user “test”  with password “test123”:
&ltuser name="test">
&ltpassword>=#!test123
</password> (make sure you have “=#!” characters in front of the word to encrypt the password and </password> is in the new line)
</user>
c. Once you are done adding the users and password, run this command on the xml file:
obfuscate export.xml
d. The file will have the following result:
&ltuser name="test">
&ltpassword>=#!NrbyhBQFJfd9oOqmVZWOXeLhBL0M/WMV
</password> (Notice that =#! Is in front of the encrypted format)
</user>
e. Change the above password to the following format:
&ltuser name="test">
&ltpassword&gt#!NrbyhBQFJfd9oOqmVZWOXeLhBL0M/WMV</password> (Here “=” has been removed and has only #! is in front of the encrypted password and </password> follows it instead of starting on a new line)
</user>
f. Save the file and use the importDomainSecurity to import the users/ roles/ associations to the IC database
importDomainSecurity -domain &ltdomain_name> -user &ltusername> -pw &ltpassword> -file &ltfile_location>\export.xml
g. In Administrator (On the left pane) -> Application Management -> All Service Instances
On the right frame select the “Workflow Users Sync” tab, then edit setting. Depending on your requirement you can either enable scheduled time sync / real-time sync.

Adding multiple users/ roles to workflow server without manually doing it via administrator