I'm building a custom CRM environment for a small NFP. I've used Salesforce in the past but that isn't an option in this case. The Salesforce I used in the past had a 'relationships' related list/module that allowed you to make any relationship between pretty much anything. E.g. between Account and Contact or Contact and Lead. It allowed us to track 'who and what has what relationship between who and what. E.g. 'Account X used to work at Account Y' but also 'Contact A is the sales person at Account B'. And so on. 

I tried to do so by creating a 'Relationship Module' with lookup fields to both contact and account but off course that didn't fully work. 

Can anyone help me figure this out please?

Matt