It is possible to create relations between cards. You can create relations between cards of the same collection, but also of cards of different collection. Cards that are related to each other will visibly show a connection line between the cards in vPlan. You can also define the type of relation between the related cards. A card can “depend” on the other card, or the card can “block” another card. If the card depends on another card, or blocks another card determines the behaviour when planned cards are rescheduled in vPlan. More information about this behaviour and the card relation functionality can be found on this vPlan help center article.