SQL & PL/SQL

I have a code in VB which compares two .xls file and databse. There is some problem with VB6 nothing can be done on my side.
Now i am asked for options on how to make it work. Can i do this comparsion of columns of .xls files and database using a plsql stored procedure.
Program Flow

*Loop through all the Group nos. in the column ‘C’ in the new spreadsheet and select the carrier key from the oracle database table (ELIG_CARRIER) for the same Group No.
*The carrier key should have the same plan_sponsor in table ELIG_CARRIER_PLAN_SPONSOR as in column ‘D’ of the spreadsheet.
*If column ‘B’ has the value other then “HMO” and doesn’t have ‘3’ as a prefix in group number then it assigns ‘0’ before the Group Number.
*Since the group numbers provided in the spreadsheet does not match with the group_numbers in the oracle database so the program suffix the ‘%’ along with the Group Number to match in Elig_Group table.
*All distinct carrier keys found for the Group No. are inserted in the newly created spreadsheet named NewCarKeysYYYYMMDD.xls
*The NewCarKeysYYYYMMDD.xls will have all those carrier_keys which belongs to the group_number exists in the new spreadsheet selected as a New spreadsheet by the user.
*The same process will be repeated to create another Spreadsheet OldCarKeysYYYYMMDD.xls and this time the Group Numbers will be selected from OldSpreadsheet selected by the User.

After creating the two spreadsheets which have the carrier keys from the New and Old spreadsheet selected by the user, the program compares the two spreadsheet NewCarKeysYYYYMMDD.xls and OldCarKeysYYYYMMDD.xls. The difference between these two spreadsheet will be inserted into a new spreadsheet with the name Diff_CarKeysYYYYMMDD.xls

I dont want the code or logic i will write on my own and when i am wrong somewhere i will ask someone to guide me... What i want to know is can this be done in PL/SQL. Please enlight me

Thanks