I have two employees, call them A and B. B is of the opinion that A is not qualified to hold the position that A does and frequently says so both in work meetings (when A is present) and in smaller gatherings (whether A is there or not). Additionally B has said extremely demeaning comments about the quality of A's work and is very dismissive of A's contributions to collaborative endeavors. A is very upset by this treatment and has complained to HR several times. B's defense is that his statements are true and accurate and cannot constitute harassment is he is not slandering A or singling A out for this "abuse" (A's words). B has been counseled not to antagonize B, but B insists that A's work is substandard and harmful to the company and B would be remiss in not pointing it out. A is considering legal action against B and the company for not acting to stop the harassment, most likely on the grounds of B's actions creating a "hostile work environment". A's qualifications have been deemed meeting hiring requirements - a decision B vehemently disagrees with. A and B hold the same rank in the company. B has threatened to counter-sue if any legal action is taken against B. Any suggestions as to the "correct" way to handle this situation?