I would cut the tall stems down, cut the cut off stems into 4-6" segments and and try to root them.
It's not too difficult, though it takes a bit of courage.
What is the weather like now? When will you be able to let them outside?
Ideally, you would give the mother plant a good chop just when you put it outside for the summer. This way, it can grow strong side branches from lower down and form a nicely branched sturdy structure.
If you have the space to grow a bunch of cuttings -- need well lit but no direct sun spot until they strike roots and begin to show new growth, then they need a strong light/sunny window to grow strong new shoots.
If you want to do this, I or someone else can post instructions.
Mine are so ready to go outside! But it's supposed to dip down in the 30's mid week. Just as well because all these flowers will have be chopped off to prune the main plants which are about 20-24" tall right now. I will cut them into segments root them at that point. I could take cuttings and propagate them now so I would have rooted plants to plant out when it's time, but I don't have the room inside, so I will be doing all that outside after the weather has settled
