should be (reasonably) simple:
add your spaghetti, linguine, ziti and chicken to the list of ingredients for that collection of meal sizes and set the pasta types to be 0.00 and the chicken to be 3.00
add a couple of custom groups (one for the pasta types one for the chicken) as follows:
set/add a pasta types custom group to be a group type of “one only” (radio input) as – presumably – you can only select one of those, add the pasta choices there, and assign to your pasta items
use the second group to include the chicken choice – (set group type as appropriate) and also add/assign that to the relevant menu items…
does that help?