When conservative Anabaptist congregations get too large to be manageable, they generally start what is called an "outreach" congregation, doing exactly that - packing up a bunch of families and sending them away. Naturally, there's often a bit of angst when the leadership begins to discuss the idea of an outreach, because you might end up being one of those families. Most of the ones I've seen happen involve people volunteering to move, but some years ago my parents were part of a church where ten families of the church were selected by lot to move. It was a 5.5-hour move to another state, and you had to have a decent excuse (such as being a new church member) in order to be excluded from the lot.
Particularly with the volunteer scenario, these outreaches take a bit of time as people figure out whether they want to move, who the other people are that might be moving, who the leadership will be, where they will move, and whether that all affects whether they want to be a part of the outreach. It's an interesting process to say the least.
I would be interested in hearing discussion about what other conservative Anabaptists here have experienced, what you have learned, and what you think is the ideal way for a congregation to expand. Why don't more CAs just plant another church in a neighboring community or even in the same community when a church is full? The time I've seen that happen, the outreach eventually took on a different flavor from the "mother" church and ended up pulling members who preferred its particular culture over the mother congregation. I don't really see that as a problem, but in this scenario the churches involved were independent/autonomous and that wouldn't be the case in many CA church outreaches due to them being simply being another congregation in the same conference.