Hi Liz. First I'll tell you a few dominance things then I'll make a post about the seperation anxiety.

Some of these things will be hard to do, but they really do help. I think the hardest is not letting your dogs sleep with you in your bed. I am not sure where they are sleeping now but it is suggested to gain dominance, they should sleep on the floor. If they sleep lower than you, they will look up to you as "top dog". Another thing is you should eat before feeding them their meals. Even if you just eat a cracker or something, be sure they see you eat first. You should also go through doorways first. I know especially with 2 dogs, this can be hard to control. You can teach them the wait command if they don't know it. Say the command, then you go through the door, then give them a release word so they can come through the door. You should be the one who starts and stops the games. If they come up to you waving toys in your face wanting to play, take the toy and have them sit or do a few commands, then you can play fetch or tug of war with them. When you're done playing, you stop the game and put the toy away so they don't think they have won.

It may not be necessary to do each of these things with your dogs. Doing a combination of two or three of them might work. Each dog is different so you can try out different dominance exercises and see what works.