credit mostly found on submission-based compilations:

• Equinity 06: Expedition - Equinity
• FLUTTERSHY’S PARADOXICALLY SOFT HARDCORE TEA PARTY - Pinkamena Party Crew - Pinkamena Party (not explicit, but it seems implied to me)
• Woodland Guide - Everfree Park Rangers - Balloon Party
• Survivors - Ponies at Dawn
• Baklava - A State of Sugar

this feels more like a release group relationship, since it would almost certainly apply to all releases in a release group, unlike say artwork