That is an almost impossible thing to do. I have a 3 sump setup, a wet/dry, a fuge and a return sump. Both the fuge and wet/dry flow into the return sump.
Trying to get flow rates exact is nearly impossible. One sump will always drain or fill faster then the other and you will end up with water every where....
Here are some pics of what I have done. If you would like some help please let me know I would be glad to help you as best I can
Here is the fuge. Behind it is the wet/dry with skimmer. There are no sponges or bio-balls in the wet/dry it is just for water volume and the skimmer.