To find all combinations of four numbers from the list $200, 245, 290, 310, 318, 360, 360, 385, 390, 405, 405, 435, 440, 442, 460, 490, 670, 680, 680$ that add up to 1814, I will systematically go through the possibilities and present the valid combinations.

Let's begin by checking these combinations.It appears that there are no combinations of four numbers from the provided list that add up to 1814. If you'd like, I can explore different ways of grouping or adjusting the criteria. Would you like to investigate a different approach or modify the list or the target sum?

Here are a few options:

1. Would you like to change the target sum?
2. Would you prefer exploring combinations of more or fewer numbers?
3. Should we allow repeated numbers?
4. Would you like to see sums close to 1814?
5. Would you like help solving a related math problem?

Tip: If you're working with large sets, narrowing down possibilities step by step can help uncover hidden combinations!