is it possible to add a variable inside the isset $_post['submit']

Is it possible to do something like this?

 if (isset($_POST['Submit_'.$_POST['ID']])) {
}

I want to do this so i can get a different submit button for all the posts, because i got a comment system, inside a posts system.. so on all the posts its a new submit button.

submitbutton is made like this:

echo "<button type='submit' class='commentbtn' name='commentSubmit_".$row['ID']."'></button>

i have checked that all the buttons gets a different name, so its just the other thing i dont get to work.