Any examples anyone can share on creating a 3 or 4-level cascaded drop-down in InfoPath using XML?

The last part is important because I only want the very last entry to be bound to a column. The others are strictly to ease narrowing down the defects (from nearly 100 possible) by cascading down the tiers.

Although I am fairly competent in InfoPath. I am a noob's noob in xml. A clear example I could reverse-engineer would be ideal.

closed as too broad by Robert Lindgren, Ganesh Sanap, Gaurravs, Mohamed El-Qassas MVP Aug 6 at 15:32

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