Postgresql EF核心中的多重相关FK

我有

segmentation

类，有一些价格范围，相关的

office

和

route

。我希望routeCountyMap表与route和county相关，但我只能为每个分段分配一次county。 例如，对于200-400分段，有A和B办公室，A办公室有E、F、g路线；如果X县有F路线，则无法进行2*00-400分段*。我的代码如下，如何安排

public class segment
{
    [Key]
    public Guid segmentId { get; set; }
    public string name { get; set; }
    public Guid organisationId { get; set; }
}

public class office
{
    [Key]
    public Guid officeId { get; set; }
    public string name { get; set; }
    public Guid segmentId { get; set; }
    public segment segment { get; set; }
}

public class route
{
    [Key]
    public Guid routeId { get; set; }
    public string name { get; set; }
    public Guid officeId { get; set; }
    public office office { get; set; }
}

public class county
{
    [Key]
    public Guid countyId { get; set; }
    public string name { get; set; }
    public Guid cityId { get; set; }
}

public class routeCountyMap
{
    public Guid routeCountyMapId { get; set; }
    public Guid routeId { get; set; }
    public Guid countyId { get; set; }
    public route route { get; set; }
    public county county { get; set; }
}

public class user
{
    [Key]
    public Guid userId { get; set; }
    public string name { get; set; }
}

public class routeUserMap
{
    [Key]
    public Guid routeUserMapId { get; set; }
    public Guid routeId { get; set; }
    public Guid userId { get; set; }
    public route route { get; set; }
    public user user { get; set; }
}