I am sure you also know the problem of ensuring that only complete and correct data sets are transferred to further status or even further data types (Lead -> Account). 

What i would thus like to do is the following: Create a validation that links the ability to convert a Lead to a list of must-have fields filled out completely. 

Example: 

Due to the inability to have different sets of mandatory fields for different status (via masks) i currently only have a minimum set of mandatory fields for Leads:

--> Last Name

--> Company Name

--> Priority

--> Status

--> Email

This is fine if they set it up. in Order to manage the data in my CRM tool efficiently i would like to force my Sales Team to provide a set of other data fields before they may convert it: 

--> Address

--> Lead Source

--> Website

--> etc. 

So my aim would be: Only when the set of fields is NOT Empty may a Sales User convert a Lead to an Account. Is this possible in Zoho.