Good idea. But for obtaining landrace seeds or adaptation agriculture movement as it has been dubbed now there is a worldwide organization that offers them. It's called GoingToSeed. I direct people there towards Permies site if i can, because to me permaculture and adaptation gardening fit hand in glove,reinforcing each other. They have a box travelling differing continents called the Serendipity Seed Swap or the European Seed Train in which people can put seeds that do well at their place and they can take what they like to try. I never had something boost my arsenal of crops i can suddenly grow as much as that. And i'm in Europe where we don't even have so many people's breeders as in US.
Exchanges is great, but i've just traveled an hour to one and there was one other man sitting at a table with scruffy envelopes of 2021. He was very pleased to see me though and so where the ten or so other visitors. my advice would be NOT to try to set up something apart, you know, like Permies only, but just pitch your idea to local seed swaps that already exist. Enthusiast gardeners are a dying breed and the grey hairs at those fairs are happy with all the younger people they can get to join and just have to come to terms with the fact that the younger generations see things in a much wider context than they do. Change goes slowly. First they laugh at you, then they fight you and then you win. There is a great book about Landraces by Joseph Lofthouse and there is David the Good who's done some great interviews about it as well.
We're also talking about breeding landrace shrubs, trees and cows and chickens, so this idea has come a long way already! You're not alone!