How to Enforce Node Dependencies and Mutual Exclusivity in LangGraph?

[pinngan]

I am working with LangGraph to create a graph where Node D must wait until Nodes A and C are both completed before it executes. Similarly, Node E must wait until Nodes B and C are both completed before it executes. Moreover, D and E are mutually exclusive, meaning only one can execute depending on the condition evaluated in Node C (Condition1 for D and Condition2 for E). However, in my current graph setup, both D and E are triggered prematurely without waiting for the result from Node C.

How can I implement a graph structure to enforce this dependency and mutual exclusivity in LangGraph?