You could probably achieve what you want using the multi-line regex functionality (Pro feature). When the program converts the spreadsheet into text each sheet is prefixed with the sheet name, e.g.
Sheet: Processed (1 of 5)
... sheet data ...
Sheet: Orders (2 of 5)
With Multi-line RegEx specified as the expression type you could search for something on the 'Processed' sheet by searching for:
Containing Text: Sheet: Processed.*?577001 728.*?Sheet: Orders