Mapping Custom fields based on dependency

Mapping Custom fields based on dependency

Scenario-: 

1. I have created 4 custom picklist fields, for BANT qualification in leads module named Budget, Authority, Need and Timeline. 

2. I have created 4 more custom fields (text) such as Budget Notes, Authority Notes, Need Notes, and Timeline Notes in leads module. 

3. In leads module, I also have a lead status pick list with 5 values 
(i) Known 
(ii) Marketing Qualified 
(iii) Contacted 
(iv) Sales Qualified 
(v) Disqualified 

Now what i want is, that above all 8 fields (mentioned in point number 1 and 2) should be mandatory to fill to save lead ONLY when the lead status is either Contacted, Sales Qualified or Disqualified, but not when its Known or Marketing Qualified 

When i go to lead layout page, it only allows me to make all of them mandatory, not the way i want, If i think of dependency fields, it does not help either unless if am missing something.