I'm sorry you're so stressed right now.  I haven't been through the same situation but was in a blended family for awhile.  My dad married a woman who had 2 sons (younger than my 2 sisters and I).  The best advice I can give based on my experience is to treat everyone equally.  My step-mom had my dad wrapped around her little finger and her boys could do whatever they wanted.  Everything got blamed on my sisters and I and we were always getting in trouble for nothing.  We always felt like the boys got everything and we got nothing.  It turned very nasty and got to a point where my sisters and I were miserable and ended up fighting daily with our dad.  He finally divorced her and everything was back to normal for us.  I know your situation is a little different and your kids are younger but really try not to favor your children over your step children.  Equal time for all, equal attention for all.  I'm sorry I'm not much help but that's the best advice I can give.  These kids are just at an age where they're going to fight anyway.  I have a 2 1/2 year old and a 5 year old and they fight constantly.  I have to separate them a lot.  Maybe you could separate the kids by ages (not parents) and plan different activites for them- for instance pull out a bunch of cars for the boys to play with and put them in a room- let the girls go in a different room and play with something else. 

Stephanie

MissD, I can't help too much with advice in this area.  I have a blended family myself.  My wife brought two lovely daughters into the blend.  I have a daughter and a son.  My son is the baby of the group, but the baby is 20 years old.  Our blended family includes 4 grandbabys, all girls ages 2 - 5 with a bun in the oven, maybe we will finally get some balance in the family testosterone/estrogen ratio.

I am having some issues with one of my own "adult" children.  I have come to the conclusion that perception is reality.  No matter what we do as a parent, our perception will never be the same as our children, hence neither will be our realities.  All we can do is our best and hope that our perceptions of our lives and those of our children are not so diverse that we can all live in the same reality.

Anyway, the real reason for my post is that if you go to the classified section of this web site and go to jobs and then jobs wanted, there are at least three ads for young ladies looking for babysitting gigs.  I hope that one of them will work out for you. 

Best wishes..