DataCracker can only generate a report for a single data file at a time. At the moment, it can't link the reports or compare them - however, this is a frequently requested feature and we will consider developing it in future.
If the data is an Excel file or can be converted to Excel file, we would recommend to combine all the responses into 1 file. You can add a new variable to distinguish the respondents (eg. Online vs paper survey). See here for more details on getting the data file: http://mktresearch.org/wiki/Getting_a_Data_File