Joined: Jul 2002
Posts: 40,863
Likes: 3,115
From: Sacramento, California, USA
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
Are you asking whether you can hang the DA group from the new bike on the old bike? Yes, without any problem.
Or are you asking whether DA components are compatible with 105? Yes, if they're all 10-speed. If not, you may have some problems. Or not. (My CX bike is a mix of DA, Ultegra, 105, and RSX (!))