Add logic to the Report rule setup

For an APP10 customer, trying to set the logic to the report rule and raised the question.

In the report rules you can point to a variable in the XML  (example  [@UNIFORM_PAYMENT_ADVICE_REP/IDENTITYS/IDENTITY/COMM_METHOD])    is it possible to add logic to this?  Example I want to remove the first 7 characters of that variable.  I tried  [&select SUBSTR([@UNIFORM_PAYMENT_ADVICE_REP/IDENTITYS/IDENTITY/COMM_METHOD], 7) from dual]    but that didn’t work.   I just wanted to make sure its possible to do what we want.

Reasoning

The Comm Method variable   is   ‘E-Mail:  jackdoug@gmail.com ‘    in order to actual use it, we need to strip off  ‘E-Mail:’

THanks