If necessary, use some sort of restraint to keep the dogs off the bed at first. I had the same problem with my dog. He had to be leashed to an eyebolt in the baseboard near the bed for a few nights so I could get some sleep. He now knows that bedtime means on HIS bed, not mine.

Just make sure the leash isn't long enough for him to get on the bed anyway. I learned that the hard way.

Or use a crate with the door closed until he gets it. Then leave the door open so he has his own 'room'.