Absolutely. This receiver is almost identical to the SC-27 I have been using for 3 years. It has a set of 7.1 inputs called "multi-channel in" as seen on page 20, box 19 of the manual on-line from Pioneers's US website. After plugging everything in from your Sherburn, set the SC-25 to select the multi-channel input from the remote. I used it this way for a while to continue to use a classic Denon 5.1 pre/pro until I got some more speakers to go 7 channel.
Pioneer Sc-25/27 manual: http://www.pioneerelectronics.com/StaticFiles/Manuals/Home/SC-25_OperatingInstructions0421.pdf
Pioneer Sc-25/27 manual: http://www.pioneerelectronics.com/StaticFiles/Manuals/Home/SC-25_OperatingInstructions0421.pdf