Have you ever taken a close look at the rule for going to ground? Its on page 24 in the Rulebook, and it is worth taking a closer look at. I would like to direct your attention to the specific wording in the second paragraph. It states that 'after the enemy has rolled to hit and wound against any of your units, but before you take any saves or remove any models you can declare that the unit is going to ground'
What does this mean exactly?
A) A shooting attack is directed a target unit. A first unit fires on the target. They take their normal saves. A second unit fires on the target. They elect to go to ground. This is fine since this is clearly a second round of shooting at the target. This is the usual way I see this played, since most people have not looked that closely at the wording under go to ground.
B) A shooting attack directed at the unit. A first unit fires on the target. They take their normal saves. A second unit fires on the target. They elect to go to ground. However if you look at the wording above you see that they can actually no longer go to ground at this point. The target has already taken saves previously this turn, so they cannot go to ground since they have already taken wounds and made normal saves. What does this mean? Fire on a unit with lasguns before you open up with your Leman Russ!
C) Or does it mean you must go to ground before you take ANY saves of any kind, or you lose the ability to do so. The wording does say before ANY saves are made, after all! it makes no exceptions and does not specify that this is on a unit by unit basis. This would mean a first target takes a normal save and then from that point on no other unit in an army could go to ground for the turn!
What is your take?