A subrule is a process fragment that can be called from the main rule definition, or from another subrule. 

To define a subrule:

1. Go to the rule definition . 
2. As a with stream definition, click the process selector at the left end of the rule toolbar. 
3. Click Add New Sub Rule.
4. Double-click the Start Rule Execution step to give the subrule a name. 
5. Define the subrule process. 
6. Click Save Sub Rule.