Attack/Move order problem

I'm working on a map(it's almost ready for release btw =P), and I have 2 abilities, All Move, and All Attack. By the end of the game you usually have pretty many units, so these abilities either order all your units to move to a location, or order them to attack-move to that location.

However, when the number of units gets to high I run into some problems. It seems as if they are taking turns being ordered to move, and the rest of the player's units are stuck. So say 5 units will move towards the target for about 1 second, then they'll stop and another 5 units will start moving, and this keeps going untill they all get there. However, the units that aren't in the current group being ordered to move are unmovable! It usually takes around 5+ seconds for them to move/attack after you have ordered them to.

Also, the selection system for who is moving currently seems to just go in a preset order, or maybe is random. Its really annoying when I have about 5 units fighting the enemy, while they have 30, but then I have 50 more units standing about 5 feet away that stop moving and are unmovable. Although this isn't a huge problem, because it usually only happens in games where the number of units gets very high, it's still pretty annoying. If anyone has experienced this before or has any ideas, help is appreciated ^^.

The solution is simple: don't have this many units. Seriously, this happens because the engine can't handle so many units; there's no way to fix this other than having a unit number limit.

Argh. That might actually be a good idea though..making a unit cap. Once there gets to be so many units that you can't control them without the All Move there really isnt much strategy anymore.

Edit: Yep, I made the most units you can have 70 and now there aren't any problems. It makes the game more fun too ; ).