Printing only relevant data

First of all, I should say I like the plugin very much. ??

I have two issues:

1. when I submit the form, any field in the form is displayed, even if it had been previously hidden. Is this normal?;

2. I have a select with just a couple of choices, say A and B. When the user selects A, another select is displayed, while nothing happens in case the user selects B (this is the intended behavior of the form).

Problem is the form receives the value of a field derived from the selection to A, even if the user selected B. Is there any way to avoid this?

This is a sort of skeleton of my current situation:

[select* your-permission "A" "B"]

[group Grades]
[select* your-grade "G0" "G1" "G2"]
[/group]

[group G1]
[select* your-exit "G1-0" "G2-0" "G3-0"] 
[/group]

[group G2]
[select* your-exit "G2-1" "G2-2" "G2-3"] 
[/group]

[group G3]
[select* your-exit "G3-1" "G3-2" "G3-3"] 
[/group]

Now, when the user selects B, anything is hidden.

When a user selects A, Grades and G1 is displayed.

If a user selects another grade from the Grades select a corresponding group is displayed (and the previous group replaced).

BUT your-exit should not be sent (or should be “muted”) in case the user selected B.

How can I do it? Is this possible?

Thanks in advance