Validate for 1 text box only

Hello i have 4 textboxes, but the user must enter data in atleast 1 of the 4. How do you do this with the validation controls?

Best,
AsafTake a look at this post

Please, don't post the same kind of question that you already posted. If any one can answer your question I promise they will. If you need to clarity or make the question more detailed, please add a new post as a reply to your question instead of adding a new post.

Thanks for the understanding.