That’s the tough part right. Where I live, there’s actually a group doing this. All just word of mouth contacts but their network is growing. So I know someone here I can ask to buy or sell. Within their group, my contact will then let the other contacts know my request. My contact will not sell to me from one of his direct contacts so they internally maintain separation. It’s well organised. Maybe a lucky in this regard but it is something that would be good to have as a common pleb community standard