You can set up the matrix for all eight violins and remove violins 2-8 from one version and violin 1 from the other. Also, if you press ctrl+alt W on Windows (or the Mac equivalent) you will get a list of patches loaded. If you want to replace patches in a matrix with those of a different instrument, you enter equivalent parts of the patch names in the boxes.
In DS, player 1 patches have P1 in their name and the corresponding player 2 patches have P2 in their name, so you can enter P1 in the first box and P2 in the second and VI will automatically do the replacements for you. As far as I know, this is not an officially supported method, and it only works in standalone mode, but I have found it very useful. Instead of P1 and P2 you could enter KLB and BA to have Bb clarinet patches replaced with bassoon patches, for example.