Don't know if this will help. A "Collection" can't help much with 1-Liners.
However a Dictionary often can.
Here is a quick idea. This has a vba reference set to Microsoft Scripting.

Sub Demo()
'//Dana DeLouis

Dim v1 As New Dictionary
Dim v2 As New Dictionary
Dim rng As Range

Set rng = [B1:C10]
v1.Add rng.Address, rng

Set rng = [E1:F10]
v1.Add rng.Address, rng

Set rng = [A5:J6]
v2.Add rng.Address, rng

Set rng = [A8:J9]
v2.Add rng.Address, rng

'// Here is your 1-Liner :)

Intersect(Range(Join(v1.Keys, ",")), Range(Join(v2.Keys, ","))).Select
End Sub

HTH
--
Dana DeLouis
Using Windows XP & Office XP
= = = = = = = = = = = = = = = = =


"Robbie" wrote in message
...

Is there a one-liner (I'll consider a two-liner for half
price) in VBA that takes two or more collections and forms
their intersection or union?

I know about the Intersect and Union methods, but those
only take ranges as arguments; I'm interested in forming
intersections and unions of collections in general. E.g.,
if X, Y, and Z have been declared as New Collection, I've
added objects to both X and Y, and now I want to quickly
set Z equal to the collection that consists of those
objects that are members of both X and Y.

Thanks,

Robbie