<human>: Could you distill the essence of the text into 1-3 sentences?

Hi all:

So I'm living with two other guys in a California house with a joint lease that expires Feb 1 (we'll call them Sam and Bob).  We had a verbal agreement (I know it's meaningless) that made Sam (who joined later) pay $175 more than my other roommate who has the same size room (I'm in a tiny room half the size).  

Recently, Bob hasn't been respecting the house/roommates.  His girlfriend lived here for 1.5 months with her dog when our lease is for 3 persons and 1 dog (we already had 1).  Bob also had his mom's 150lb undisciplined dog over that tore up property and barked all night for 9 days.  We didn't bring this up because Bob was out of a job and we didn't want to make things harder, but he now is employed.

So Sam called a house meeting last week.  He first suggested splitting rent 3 ways even which I was fine with, and we all agreed verbally.  Then we brought up the girlfriend and dog in a tiny 1 bath house, and suggested that she pay utilities and a little rent (like $50-$150).  Bob freaked the fuck out, and is now refusing to even pay 1/3 of the rent like he agreed to.  Sam is only willing to pay 1/3 this month.  I'll up my rent to 1/3 but I refuse on principle to cover the difference.

Now I know that Joint and Several liability essentially means that I have no recourse and am liable if they don't pay, but I'm wondering what I can do to minimize the pain.  

From what it sounds like the landlord has a choice on who they sue in the event of non-payment.  I'm thinking about contacting the landlord, laying out the issue, and asking him to not sue me.  I was also contemplating letting him know that I'll be happy paying an extra month or two of my 1/3 of the rent if he evicts us, as long as he doesn't sue me, but I'm not sure if this could be construed as bribery or something.
<bot>: Two of my roommates are bickering about rent and may not pay. We're in a joint lease with no contracts between us.  I want to know what I can do to make my situation as good as possible.