Making my own DIN sync box

[Bogdan Wies Taw Raczynski]

I was curious how hard it would really be to make my own DIN sync box?
I have two drum machines that only have a DIN on them (606), and want to 
sync them to a 707 (707 being the master of course).  What would be 
involed in making a box where I can put in as many sources, and have them 
output to a single source?? That didn't make sense.  let me draw it out. 

  707
   |
   | <--din cable
 __V__
|     | <-cheap din sync box
|     |
 -----
 |   | 
 V   V
606 606

I imagine if it's simple enough to have 2 din's, then I could probably do 
many more.  Right?  BUt for starters, I'm curious if this is even 
feesible or realistic. 

Any hints, ideas, help, schemastics, would be greatly appreciated. 

thanks!

bog