This has been so stressful. My fiance is a very well known…

This has been so stressful. My fiance is a very well known around the world for what he does and we've made many friends in other states and countries. We can't afford to invite the hundreds and hundreds of people that have been sending us well wishes and asking us about our upcoming nuptials. We also don't want to be rude in expecting people we love to travel not just across country, but around the world to be at our wedding. Many of these people (300-400) will be in Las Vegas for a separate event in a couple of months. It was recommended to us to have a party while we are all there so we can have fun and celebrate with our friends, although some other have suggested it is rude to do this and not invite them to our wedding. My question is, is there an appropriate way of going about this? We absolutely do not want or expect gifts, and are just wanting to have a very informal "the more the merrier" kind of hotel room suite party and let people come and go as they may. If it is presented just as a "party" and in no way a shower/engagement party/reception/etc, would this be okay? Do we leave out any talk about the nuptials altogether or acknowledge that we understand it's rude to expect people to fly from other countries for our wedding? Can we say something along the lines of "no gifts" or "let your presence be your gift" or do we just not talk about gifts at all? We really do not want to be gift hoarders or rude, we just want to celebrate and have fun with people we enjoy during the one time per year that we are all able to get together. It has also been suggested that we just get married in Las Vegas during that time, but as all of our family is here in a different state, the ceremony is planned here. Any advice or suggestions are appreciated.