group up the control with submit button

let's say on the same page i have 3 sets of submit
how can i make it possible to press enter and it is using the corresponding submit button to the current group of control i'm working on
 ex.    i have textbox with  search button   ,     textbox with new button,     textbox with delete button
 
when i put something in the 1st textbox which is the search  and press enter  it will submit with search button
when i put something in the 2nd textbox which is the new  and press enter it will submit with new button
 
Thank

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