You can insert some parameters to control it.
Try to create 3 parameters TRUE/FALSE, cone, ret. cyl..
Then one parameter text with multvalues with this 3 options.
create a code that if the multvalue selected is CONE...then only the control cone will be TRUE, the others 2 will be false.
then create a form, with the main button with that multvalue (put as a radio button, its nice for it), then create 3 groups that in each one u'll put to enable just when the right control is TRUE.
So in the radio button when u select CONE only the group 1 will be enabled, if u choose CYL onle group 2....
In these groups u put the parameter u want to edit for each kinp of part, and to enable or disable these parts put in the IF of the code u created to control the boolean parameter.
Sry about my english, i hope this answer can be usefull to u.
Túlio Barata
IV 2013