@aalnabelsi I think you could do this with KNIME nodes by identifying the ‘blocks’ in the Excel Sheet and then applying the rules you described. The secret is in marking the start and possible end of the table/bock and then filling the empty lines with the missing values node as described here:
Please also note the linked threads there.
The sheets themselves might be identified by reading the sheets and selecting the ones that have the name part you described.
Since these seem to be common questions I think about writing a blog about them.