Building a groupset on "probikekit"

can i mix and match when building a set? im looking to get ultegra derailleurs, 105 brakes, 105 shifters and a dura ace chain…am i just not savy enough to figure it out or whats the deal.

Ultegra derailleurs:
http://www.probikekit.com/display.php?code=D0006
http://www.probikekit.com/display.php?code=D0009

Dura ace chain:
http://www.probikekit.com/display.php?code=K0057

For 105 shifters / brakes you could check out trisports.com:
http://www.trisports.com/shimano-105-brake-calipers.html
http://www.trisports.com/shimano-105-sti-10-speed-shifter.html

Good luck on your build!