The only way to display search results from multiple tables is to create a join table that hold a record for each record found in each table, and has a link to the record id of the appropriate table. So if you found 10 records in 2008 and 15 record in 2009 your join will have 25 records, does this make sense?
Then you would have a go to button on the record that called a script that checked which source table the record is related to and then used one of multiple Go to Related Record script steps to display the appropriate record.
Its not simple but might work for you.
Another suggestion is relating to the fact the data is split in the first place. Was you splitting of the data purely on the basis of a single calculation? If so I would suggest a different approach.
You could create a field the user has no access to that distinguishes the version of the calculation to run, so a 1 for version 1 of the calc and a 2 and so on, in case the calc changes again.
The the Calculation in question woudl start with a case statement that simply read
CalcVersion = 1 ; [Original Calculation] ;
CalcVersion = 2 ; [New Calculation]
Then set the ValcVersion field to Auto-Enter the value 2.
Would make searches and maintenance easier for you.