Creating Array From 2-dimensional Array

I'm new to arrays. They seem promising for what I want to do though...

Heres where I'm at. I have some data like this:

items freq 1 0.5 2 0.5 3 0.5 4 0.25 5 0.25 6 0.125

Now, I've created a 2 dimensional array, as such:

Code:
Sub testarray()
Dim arr1 As Variant
Dim rng1 As Range
Dim lngX As Long

Set rng1 = [A2:A6]
ReDim arr1(1 To rng1.Count, 1 To 2)
For lngX = 1 To rng1.Count
arr1(lngX, 1) = rng1.Cells(lngX, 1)
arr1(lngX, 2) = rng1.Cells(lngX, 2)
Next
End Sub

Now, what I need to do, is create an array for each freq of all the items that share that freq. Essentially I need this:

0.5 {1,2,3} 0.25 {4,5} 0.125 {6}

Now, I was thinking, if I could create a dictionary object and make the key the freq (so my keys would be 0.5,0.25,0.125) then I could assing the "item" an array (or another dictionary) holding the items that apply to that freq.