I'm not sure if it is possible to implement a quest chain like this. I've created a basic outline of the flow. How do I use Quest2 as a requirement to continue both branches?
.............Quest1
__________^____________
|........................................|
QuestA1+Quest2...........QuestB1+Quest2
|.........................................|
QuestA2.............................QuestB2
Quest1 has a player choose between branch QuestA1 and Quest B1.
QuestA1 and Quest2 can be done at the same time. QuestB1 and Quest2 can be done at the same time.
Player must complete QuestA1 and Quest2 to be offered QuestA2
OR
Player must complete QuestB1 and Quest2 to be offered QuestB2