Could you edit the field, set Validation Rules to validate[required.cutom[number]] to see if it works? See
github.com/posabsolute/jQuery-Validation-Engine#validators
for list of supported built-in validators to see if it could be used to handle your requirement ?
I got one more question regarding the group registration duplicate account. For now, is there any solution to prevent same email address been registered in same group registration?
