I was thinking ¶s, but totally as a guess. I googled pluralized pilcrows and couldn't find anything...
-----Added 5/27/2009 at 02:35:09 EST-----
Ok. So
this is from some manual where I think they are giving rules to their own company, not like an MLA. But they say that if you are citing two paragraphs, you write:
"(see ¶ 5.1 and ¶ 5.2)"
But if it is more than two, you write:
"(see ¶¶ 5.1, 5.2, and 5.3)"
If you follow the link, see page 8 of the PDF. Or to be more precise

§ 4-22.
It does address sections, too, but not pluralized. I'd follow the same ¶ rule, probably.
-----Added 5/27/2009 at 02:35:55 EST-----
thanks for exercising my brain!