Be aware that many churches have an "open door" policy. My church, for example, welcomes anyone and everyone to any worship service, including a wedding. A stranger off the street could walk in and witness a wedding ceremony.
If you want to keep your wedding truly limited to your family and attendants, I suggest you talk to the church personnel about their policies regarding walk-ins.
In other words, are you prepared to have a bouncer at the door in the event that some of your reception guests want to be there for the ceremony?
It's totally OK to invite a small, intimate group to the ceremony and a larger group to a reception. What's NOT OK is just the opposite--inviting people to the church and then not to the reception.
That being said, many people resent being made to wait for hours or to travel long distances between a ceremony and a reception. So, except for immediate family and various closest friends, I would not ask people to do this. If you want a distant reception (distant enough to require a hotel?) you might even consider having the two events on different days, to give people time to travel, rest, and refresh.