If you don't find an answer you like you could do it a silly way like this:

• Make the main snippet only do half of the snippet you have now, up to the choices.

• Then create different snippets based on all the choices you have.

For example create a separate 'chair' snippet with the prefix chairbf.

Now when you choose 'chair' in the main snippet you can type 'bf' after to get the completion for the chair choice snippet. This separate snippet will have the chair submenu options plus the ending of the main snippet you have now.

You'll have to create the other choice snippets, for 'nothing' and 'all', as well.