I don't think there is a neat way to do this. However, you could change the title of the whole family (do this by going to 'My Account', then click on 'Rename'), say to 'Mother's Family' . After this, click on your mother to focus the tree around her, then print. Rename the tree for your father, then print his side of the tree as well.
It's a bit laborious but it should get you the result you want. Hope this helps!