Usually the same bonuses does not stack with exception of dodge.  However, in Master of the Wild, pg 36/ 37, it states "one ring of animal friendship adds 12 HD to the character's limit, a second raises that to 24, and a hand of glory allows the use of a third ring for a total of 36 additional HD of animal companions."  This is different from the norm.  If I were to wear two rings of protection +5, I would still only gain the benefit of +5 deflection.  Why does ring of friendship stack?  Are there any other such exceptions?
				
			 
				 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		