Go to dickblick.com. They've got a nice aluminum brush box. It's got 2 rows of springs inside to stick your brushes in and hold them in place. Check it out.
put them in their own seperate container or partition of the box. Remeber to condition them after you use them with something like Xcaliber brush conditioner. Its synthetic so it wont degrade the bristles. You should rinse it thorughly with reducer or mineral spirits before you drag it through the paint when you get them out for a project. If you are goung to use it say the next day you don't need to condition it unles you want to.
Most guys use a non-drying oil,that won't go rancid.Like Neets Foot Oil,Mineral Oil,motor oil,transmission fluid.NOT Linseed Oil,Tung Oil,Canola,etc.The oil stops the very small amount of paint still in the brush from drying,and helps maintain the shape.Check the TechOmatic for more on Pinstriping.There is a good page about brush care on mackbrush.com