How to create a collection of sets and how find its subcollections of specified size

ordered pairs for example say a collection of set {[1,2,3],[3,2,4],[1,2,4]}
subcollection of size 2
{[1,2,3],[3,2,4]}
{[3,2,4],[1,2,3]}
{[3,2,4],[1,20,4]}
{[1,20,4],[3,2,4]}
{[1,2,3],[1,2,4]}
{[1,2,4],[1,2,3]}

Is it possible to do this program below without finding all subsets
sage: s = set([1,3,"two"]) # make a set from a list of items
sage: t = list(subsets(s)); t # this is the list of all subsets of s
[[], [1], [3], [1, 3], ['two'], [1, 'two'], [3, 'two'], [1, 3, 'two']]

sage: for x in subsets(s): # subsets(s) is an iterator, so you can loop through it
....: if len(x) == 2: # and extract items of a specified length
....: print x
....:

[1, 3]
[1, 'two']
[3, 'two']