not exactly no:
in standard games each basalisk fires separately, so they dont barrage off of each other. (unlike say, units of mortars) - however, if fired indirectly, then the unit has suffered from an ordnance barrage so will suffer the appropriate Ld modifiers.
in apocalypse, things can be slightly different, but lets not confuse matters here...
oh, and this belongs in the rules forum... your friendly neighbourhood mod will be here shortly to throw it into the right place.