Some hire rooms, and some are put on at their own work premises.
DC Thomson's having a few properties dotted around town, end up having a handful of parties spread across various locations.
The 3 examples above all took place in 1966.
The top photo is one of the parties held at Kingsway. I say one of because they actually had to split the '66 do into 2 parts. The one above being the 5 to 14 year olds section.
The middle picture is the party gathering at Lindsay Street.
The bottom photo is the kids tucking into their Xmas banquet in Bank Street, with one of the invites having a bit of trouble with their hat!