public IEnumerable <StopGroup> TransferTargets(int radius)
{
return(Stops
.SelectMany(s => s.Transfers)
.Where(t => t.Distance <= radius)
.GroupBy(t => t.Target.Group)
.Select(t => t.Key)
.Except(new StopGroup[] { this }));
}
public IEnumerable <Transfer> Transfers(int radius)
{
return(Stops
.SelectMany(s => s.Transfers)
.Where(t => t.Distance <= radius));
}