Need to create many to many relationship between accounts and contacts. I am able to create a many to many relationship but there is the built in 1 to many that it doesnt let me hide or disable.

I can of course use a custom extension and create many to many with the account, instead of using contact extension but I need to hide the contact extension. How do I do that?

I would prefer using the built in Contact Extension but need to figure out how to hide the build in 1 to many!. help please.