formatting text from within vi

[David Banning]

I am familiar with the !}fmt used in vi to reformat a paragraph, but
I wondered how, or if it is possible to do more complex formatting. 

I am thinking specifically of numbering, or creating points. I am familiar
with the 

.AL
.LI
point 1
.LI
point 2
.LE

that can be run with "nroff -mm", but I notice that it can not be run
successfully with, say "!}nroff -mm"  from within vi.

Anyone have an idea?