Alternative options to default gnome program

Miroslav Ruda on December 15, 2010 said:

Thanks for tb_3.1 version, it works with thunderbird 3.1.7 as expected. What I’m still missing is possibility to choose alternatives for opening, already predefined
in gnome, visible for example in nautilus. For example, you may have several associations with .pdf (acroread, xpdf, gv, …), one is default, others can be used
from nautilus using “Open With”. In thunderbird, I can only open the attachment with default program or choose path to command myself, but I have no chance to select non-default possibility from already defined alternatives in gnome.

(from http://opencoding.wordpress.com/2010/12/11/is-openx-gnome-open-still-needed/)