for and example of populating 1 drop down box filling a second with a variable number of options based on the first selection. Note examples are given for both AcroForms and Live Cycle Designer so make sure you read and download the LiveCycle Designer example.
I need to do something similar to this.
Specifically, I have two combo fields containing the values 4 - 20.
Whatever value is selected in the first field, only values above it should be available in the second field.
And equally, whatever value is selected in the second field, only values below it should be available in the first field.