Thank you for your post.
Whenever you create a button, you set the hand cursor. There is no conditional way to turn on and off the cursor. Therefore, you may want to consider two nearly identical layouts. One with the button, and another without the button. If this is all being scripted, then depending on the contents of the field, you can decide which layout you want to access.
Let me know if you need clarification for any of the above steps.