Required Field Validatior Question

This may be easy, but I must be overlooking the obvious.
I have two command buttons on the web form, with 4 textbox's.
When I click the first button, I submit the values of the first two textbox's. When I click the second button, I submit the values of the last two textbox's.

Here's the problem. I'm using required field validators and I need each button to only validate its related two textbox's, where now I checks all controls on the form. Any ideas?

I don't use validators (is that bad?) .. But I validate them myself in VB code, and I have a label on the page (lblError)... and if something required is not filled out, i make the lblError visible and set its Text property to the error message.

Using the required field validators, you have the option to do all of your validation on the client-side, thus avoiding the nasty roundtrip. I may just have to write my own javascript.

You could always use a couple of custom validators.

Associate the first with button A to validate boxes 1 & 2 and associate the other with button B to validate boxes 3 & 4.

Bear in mind that the client-side validation isn't supported by all browsers...