How do I address a wedding inviation to my coworkers?

I'm sending one invitation to my office. On the outer envelope I am planning on putting the company I work for and address. On the inner envelope should I write out all eleven coworkers (and their guests?) or how should this be handled?

All of my coworkers are invited as well as their guests... but that would save us like twenty invitations if we just had one for each office.....

I personally would send an individual invitation to each person in their office. I invited all of my coworkers personally. It's much easier to do it this way, especially when you are inviting their spouses and significant others.

Even though others have sent group invitations before, it is much more personal to invite each person individually. But if you would like to send one invitation to the entire office, I would address the envelope to the name of your company/department and use the business mailing address. For the inner envelope I would also recommend you just use the department name; I would not write out all 11 co-workers on it. Then by word of mouth you can let your co-workers know that their spouse and mates are also welcomed to join them.

Just as an aside:
I have planned social events for years and I disagree with your coordinator. There is no way to determine how many of your 200 invited guests will attend. I have seen weddings where couples have assumed a lot of their guests would not attend, only to find out over 95% rsvp'd and came. While you do not have to send out RSVPs. You definitely should be prepared to serve refreshments for 200 guests and not 150 guests. It is always better to have more food than not enough food.

You're worried about saving on invitations? But what happens if all 200+ show? It's been known to happen.

I think that u should give one to each person idividualy thats what I did

I don't think a group invitation is appropriate. That's fine for a cookout at your house, but not for a wedding. Each guest gets their own invitation.

Your suppose to give everyone an invitation....don't be stingy with them... you'll look like a jackass. Everyone gets their own and you should ask payroll to give you their home address and send them there. Why are you not RSVPing?? Aren't you planning to feed people??

You need to send one invite to each guest/couple. If you do this the way you proposed, you'll make each person reasons for attending or not attending public to the whole group. Each person should be able to submit their RSVP separately. If you are doing this for budget purposes, you should reconsider inviting all of your coworkers. I am betting that if you are ONLY inviting coworkers and no guests, the invitation will not translate to them well and you may find many of them think they are allowed to bring a guest, adding to the cost of your wedding.