Generating a choice list for a parameter automatically

[RobertKnapik]

Hello,

I would like to create a python script tool with three parameters. Choice list for a parameter should be genereted automatically (like here: Generating a choice list from a field) but depending on the selection from the list. 

For example, if for first parameter we select from automatic list the value "12", the automatic list for second parameter should be filtered to value "100", "200" and then If we select "100", the list for third parameter should be filtered to "1000","2000", "3000" etc. 

Column 1 (parameter 1)	Column 2 (parameter 2)	Column 3 (parameter 3)
12	100	1000
12	100	2000
12	100	3000
12	200	4000
13	400	1000
13	400	2000
13	300	1000

Do you have any idea how to modify the validation code from here: Generating a choice list from a field?

Thanks,

Robert