Return value of entered data in registration form

Hi i have a dropdown menu with 5 choices that need to be visible on every registration (this is mapped from Community Builder).
Principal, Teacher, Parent, SNA, Other
For certain events if a user has chosen e.g SNA then they are not allowed to register as its only for Teachers.
I was thinking of creating a custom field that would only show on specific events where only Teachers can register.
If I could return the value "Teacher"  from the drop down into my custom field  then I can do a validation to prevent a user from booking.
How can i do this please?

Sorry, the question is not very clear to me. Could you please explain more details about it?

Tuan

Sure
Field 1 = Dropdown
Values = Principal, Teacher, Parent, SNA, Other
Visible on all events

Field 2 = Text or Hidden?
Value = return (value from Field 1)
e.g if dropdown value from field 1 = "Teacher" then this value would be "Teacher"
Visible only on specific events

Server side validation
teacheronly (checks if Field 2 has value of "Teacher")
if Field 2 Value !== "Teacher" { return false }
else {
return true }

I cant put the validation on Field 1 because sometimes I want to allow any type of user to register.

Hi

That's not possible. We do not have an option to have value of field 2 generated base on the selected value of field 1.

Honestly, I do not understand why you need to have field 2 here. Wouldn't you be able to get the value of field 1 directly ?

Tuan

No problem.
The reason I cannot do it on field 1 is because field 1 is needed on all events.
For some events, I am trying to prevent certain types of user from booking them. For example, sometimes I don’t want a parent to book an event that is for teachers.
Other times I want to allow parents and teachers to book an event. So you can see why I cannot do validation on field 1