I don't think so, Jeff, though some abc packages might offer this as an extension to the standard.
There's nothing I see in the abc 1.6 standard that provides for "da capo" and similar directions and symbols.
Barfly, the abc package for the Mac, offers user-definable symbols that are extensions to standard abc. The "segno" (sign) symbol is among the default extensions, according to the documentation; you insert it like an ornament. But I've never tried using that or any other user-defined symbols. Further, even if you get the "segno" in the right place, I don't know how you'd go about writing the directive to the player ("D.C. al <segno>," if I remember correctly).
The abc 1.6 standard does provide commands to indicate the parts of a tune and the order in which they're played. So, suppose you have a tune which is played ABCB. You can insert
P:ABCB
in the header of the tune, and
P:A
before the A part,
P:B before the B part,
etc.
I tried this out in Barfly and it does work -- but only to the extent that it plays the tune parts in the correct order when you use Barfly's audio playback. It doesn't display any indication of the parts in the sheet music, which I imagine is your objective.
If you're willing to sacrifice professional-looking notation, I think you can provide a workable directive to the player by inserting a line such as "Play ABCB" in various nonstandard, workaround ways. You could write that phrase in a part line (P:), as a "chord" at the beginning of the A part, or in any of the header fields that display when you print from whatever package you're using.