"Distributing" a sequence among other sequences - sequence

Question

I have an IObservable that produces a sequence like this:
A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4, D1, D2, D3, D4, ...
I would like to have a method:
IObservable<T>[] Distribute(IObservable<T>, count)
That, when called on a IObservable, would produce other IObservables - four, in this case - so that the output of each one would be elements from a relative "position" in the original sequence (pseudo-code):
GetOutput(unzipped[0]) = { A1, B1, C1, D1, ... };
GetOutput(unzipped[1]) = { A2, B2, C2, D2, ... };
This is identical to a person dealing cards to N people (N = count), when you give one card for each person in sequence, then start over.
The questions are:
Is it possible to get that functionality with existing Rx methods?
If not, how could I implement it myself? I feel that using Where with a modulo division in the index could be acceptable, except if the answer to question 1 above is "yes"...

Answer 1

When in Rx, you generally stay in IObservable land as long as possible. So a more natural signature would be IObservable<IObservable<T>> Distribute(IObservabe<T> source, int count), which would look like this:
public static IObservable<IObservable<T>> Distribute<T>(this IObservable<T> source, int count)
{
var toReturn = source.Select((t, i) => Tuple.Create(t, i))
.GroupBy(t => t.Item2 % count)
.Select(g => g.Select(t => t.Item1))
return toReturn;
}
You can get it as an array like this:
public static IObservable<T>[] DistributeArray<T>(this IObservable<T> source, int count)
{
var toReturn = new IObservable<T>[count];
for (int i = 0; i < count; i++)
{
var enclosedI = i;
toReturn[enclosedI] = source
.Where((t, j) => j % count == enclosedI);
}
return toReturn;
}