Do what every you feel is ok. I've seen both approaches in my office. I've seen where people invite everyone or no one and where people invite only thier good friends at work. I think the people that aren't your friends will understand and if they don't, I really wouldn't worry about it. But if you want to invite them all but don't have enough invitations left then maybe post one. But since you don't have room for all of them if they do decide to come, then why don't you not invite anyone from work. And then have night out with all of your co workers later and invite your new husband... Best of luck!