As of today:
I have been saying it from the begining, that I wasn't sure if I was going to keep the girls.
My goal was to get them fat and healthy and reevaluate the situation.
It is with heavy heart that I am thinking, not 100%, of sending the girls back to the rescue. 
(This of course could change at any moment, nothing is Solid 100% yet.)

There are a few reasons.
First Raven has lower ring bone. (She got injected with corticosteriods and some kind of acid that starts with an H.) While, Duh..., this isn't a death sentence, I have to face the fact that it takes a lot of time to manage and money.
I board my horses and I can't see paying $320 a month on a little mare no one will ever ride or drive. If I could keep her at home that would be different, easier. But $320 + management on a pasture sound horse while I have 3 others too... gets spendy. (Since they are no longer in the same stall I don't get the board break.)   This is sort of icing on the cake, the big issue is below: 

I have a lovely barn. All of our fencing, except the round pen (panels) and arenas (PVC piping) are T post and tape with some braid. Not what I call substantial stuff. It is certainly fine for horses who respect fencing. But lets be honest. If a horses doesn't "want" to be in a paddock, it isn't going to stay in the paddock.

We have been working on seperating the girls. Seperate stalls, seperate pastures. It's not going well.
If they get more that 20 feet from each other all hell breaks loose. Rook has kicked through wood on the stall door, ran through fencing, ripped a cross-tie out of the wall, calls/screams, rears, and generally has a panic attack. Raven, while not as bad, is set off by Rook and becomes a total jackwagon.
You can not bring one in and leave the other in the paddock. If you do, at least 1 horse, possibly more will be out and a lot of fencing will need to be restrung. They don't care about the electric, which at this time is high enough to cause me to pee myself if I touch it, yeah, ask me how I know that.
You can't take one and come back for the other either. It must be both together every time.

Oddly, Raven is "ok-ish" if I take her away from Rook, but not if I take Rook away from her.
When I say ok, I mean, tolerable. Just a little drama. The longer separated, the worse it gets.
Rook, well, she don't like it at all!! 

While no one has complained yet, I can't help but feel it's getting old for the barn help and BO. It's getting worse not better as we work with them. They are stronger and have more fight in them to get their way to always be within reach of each other.

I will get some video tomorrow so you can see what I am talking about.

I am toying with the idea of sending Raven back and keeping Rook. (or just sending both back to the rescue.)
Possible keeping her in the round pen for a week or so until she adjusts to the idea that Raven is gone.
I have their safety and the other horses safety to consider though, along with property damage and public safety.

For now they are in basic training for ground manners, leading, standing tied and general handling. 
I have 6 more weeks of training paid for, so that's how long I have to decide what to do.
(The time frame I have given myself to decide what to do, it's a guideline, not set in stone.)   
It is frustrating for my trainer as she has to have them together when working with them.
IE One tied up out side the arena, but it's still a huge issues for both horses.
They are constantly trying to get to each other and not paying attention to the training.  

They are happy enjoyable horses, as long as they are together.
As it stands now, I can't see ever being able to take Rook for a drive and leaving Raven behind.  
   
I need ideas/suggestions. Remember, I am not a trainer and I am personally limited in the physical aspect of this as well.
I do have a trainer and a very accommodating BO, who are both working to help.
BO has offered to change their paddock fencing, my money-her labor. I really do not want to buy her fencing.
(I have already financed a mini run in shelter.) 
While I have a trainer, my horses are not at her location. She comes to me. 
The barn help and myself also handle the horses, so the method needs to be something we can ALL work on together.  
Consistency is going to be REALLY important here.

I feel like shit and that I am letting these mares down for even thinking of this.
I know they would have died with out me. I know I am trying to give them the best chance possible.
But I still feel like shit.

Ideas? Thoughts? Floggings? Flow Charts?