Spawn groups of enemies and move them together?

I'm making a game similar to waves mode in Geometry Wars Retro Evolved.

Enemies spawn in a line and then move either vertically or horizontally, bouncing off the borders until killed.

I used bullet movement for the enemies and it works fine EXCEPT when the enemies (bullets) are off screen, their collisions or speeds or something gets messed up and they get out of line with their 'friends'.

Is there some setting I can change so they work properly when off screen? Should I not use bullets? PLEASE HELP it's bugging the crap out of me and ruins my game!

BONUS QUESTION: Is there an easier way to accomplish moving them all up/down and left/right and/or spawning in waves ?

if ='s were the bad guys going up and down;

============== enemies in a line, like they spawn and are supposed to stay

==

     ============ after you move to the right and two go off screen (they get out of line like their speeds changed while of screen or the collisions register differently than their friends still on screen)

Here is a url link to my project file home.comcast.net/~xyz1346/L1am/helpme.capx

I'm pretty sure I fixed it; I think it was a bug with the collision box (object was bouncing multiple times when it hit a wall).

I also had a problem with the last horizontal-moving guy in each wave not lining up with the rest of the guys spawned with him, the X coord was a little off and as they bounced off walls it got more and more off, Couldn't figure it out so I just downsized the layout a bit and removed him and it works!