Sum Sudoku Relay (#550)
http://www.thegriddle.net/550

513642 623145
364125 361524
132456 135462
256314 542613
421563 456231
645231 214356

214635 613245
652143 461523
126354 125364
345216 534612
431562 256431
563421 342156

251463 265143
642351 412356
126534 521634
534216 634215
365142 356421
413625 143562