Bind 2 Fields Data With One Textbox?

i have a form issue and return form. where Issuer_ID is the primary key, this form uses for boht emp and for student issuing book. at run time the user has to select a radio button for student or for employe. if he select student so after entering the full information when he press submit button so student query is execute and data stored in database, keeping the Employee field null, and when user select the employee radio button and after pressing the submit button, so employee querry executes and stores data in employee field, keep the student filed null. remmber and Student ID and Employee ID or foreign keys in isuee and return table and radiobuttons are not the part of database, its just on form.

now i want that when a user gives his issuer ID and at the lost focus event of issuer id, it is checked that if the record exists so the data is bind on the form, if does not exist so the user has to make entry, but if the data loads on form so how user will find out that this data is of student or of employee?