I am trying to set up a local business networking event attendance/ registration form.

the idea is that everyone registers when they attend, whether they are a member or not, however guest are only allowed to visit twice and pay a guest fee of £5 before they are asked to become member. Members are allowed free of charge.

Is they a way to validate if a guest has attended (submitted the form) twice? maybe based on their email address & name entered and send an email to the admin, also maybe show some free text asking them to join?after submission?

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the form has some simple information
Name (text box with validation)
email address (text box with validation)
company name (text box with validation)
Member (Radio yes/No)
Home Group (dropdown with validation on visible if they answer yes to member)
Twitter handle (text box with validation)
Event Reminder (Radio yes/No)
Submit button


Any help would be greatly appreciated

Thanks in advance
Gerald