Awwwwwwwwwwwww, what a cute picture and what wonderful dogs!
I used to have borzoi and lost both of them this past yr, along w/one of my collies (that's 3 dogs in one yr! Where's some Prozac--or a BIG margarita?). They are similar to greyhounds in many ways, except, of course, for the shedding. Mine were very predatory and I had many a close scrape w/neighbors' pets--and many dead animals in my yard. Luckily, they understood other big dogs and got along w/larger sizes. (Smaller dogs, not to mention cats, were viewed as snacks.) I recommend choke chains when you're on a walk... no matter how perfect you think your dogs are, you never know when that instinct will kick in.
I hate breed books that say greyhounds, borzoi and afghans are recluses or aloof. Any dog will be aloof if you stick it out in the yard and ignore it. A dog that is raised to be part of the family pack will be friendly and a great companion.
I don't know about your greyhounds' sleeping habits, but my borzoi did prefer to sleep either at the other end of the bedroom, or in another room altogether, whereas my border collie and rough coated collie want to sleep on my face.
They have to make do w/the space on the floor next to the bed.