I've definitely seen Petershill v Bellshill at both old and new Petershill Parks, I'm sure we've also played them at Ashfield while the new ground was being built.
I've saw the reverse fixture at new and old Brandon Parks, the Matt Busby, Rockburn Park and when they were sharing with Vale of Clyde at Fullarton Park.
Edit: Confirmed we hosted them at Saracen Park twice in 2006-7.
In August 2007 our sectional tie was moved from New Brandon Park to Thorniewood's Robertson Park.
Edit again: Done a bit more digging, we've also hosted Bellshill at Atlas Park in 1907, 1911, 1913 & 1914. We hosted them at Cathkin Park in 1915-16 as our new ground was being built, and Perthshire's Balmore Park the following season as it still wasn't ready. We finally did host them at Hawthorn Park after it was much delayed and opened in 1918.
Can't find any record of cup ties at neutral venues.
Petershill v Bellshill at 7 venues
Bellshill v Petershill at 6.