Wedding Forum - How do you handle it...

I have found that since we started planning our wedding, everyone is on at me for an invite. I am chuffed to bits that so many people want to share my day but its just not possible! There are only so many people we can invite, we are lucky enough to be able to have 200 for the evening and seats for 80 at the ceremony, but we have already gone over! Our ceremony venue has said that if more come its fine but they will have to stand, and we have that covered in regards to who wil be standing.... and cost wise theres only so many people we can afford to feed! We have about 220 + on the guest list for evening, obviously we are assuming that not everyone will come, and not everyone will be there at the same time (have told the other bike clubs to come 9ish) so we should be able to cover ourselves.
However, there are people messaging me asking when the wedding is, and saying how they cant wait... and they are not actually on the guest list! Me and h2b have such big families and a big circle of friends, so mostly are only inviting friends who we both know who are part of our every day life (with a very few special exceptions) and family members.
How is best to go about saying "your not coming" without causing offense and upset.... or shall we just wait till closer to the time, look at rsvps and maybe stick a couple of extra on to come to the evening do?

That's what we did too, we had an A and a B list. Definitely tell people that numbers are limited due to space, and if people complained to me I would tell them that the mothers had put their oars in an insisted on having some people too. That way the venue and the mothers can be blamed!

Just tell them you've only got so much room and cant go over the amount, they should be fine with it, a and b lists sound a good idea if you get so no replies