Scanning multipage doco and cropping

[kalpana]

Trying to scan in a Multipage document (40/50 pages) using Xsane, but need to crop pages differently...
ie the document has been photocopied using A4 size, but the original document was about A5. Therefore when it was scanned (from a book), they have turned the book to best sit on the photocopier, resulting in some pages being at top/left, others top/right, other bottom/left etc.
Therefore, I cannot just set a standard crop for all pages, and basically have to scan in using A4 size.
Is there any EASY way to do this?
Have tried using "Edit Image" under the "xsane multipage project" dialogue, but appears you can't crop in there....
Any suggestions welcome!
Thanks.