Check out Seed Savers Exchange about using innoclulants.  Used for all legumes.  A farmer friend told us about it many years ago.   It is a powder you mix with your seed just before planting.  It increases your yield.  It really works and it is natural.  Seed Savers tells about and there are responses from users you can check out.  Your seed catalogs, we use Johnny's Selected Seeds, always have a section tucked in the pages for all peas, beans. etc. listed.  We have never had any problem with things next to each other.  It does matter if you are saving seed for the next year.  The biggest thing we do each year is rotate our plantings.  Corn, etc. this year, is moved somewhere else in the garden the next year. Different vegies deplete the soil in different ways.  Open pollinated corn will cross polinate  if you have two varieties next to each other.    The corn develops strangely and sometimes it crunches.  Needs to be in two different gardens with a lot of distance.   Sorry, probably more than you wanted to know.