How to dynamically create Dropdownlist by checking on data from 3 tables

Question

I have 3 tables - users, roles and userRoles. Here userId, roleId and userRoleId are their respective primary keys and userRoles table contains foreign key of users and roles. Now in viewbag, I want to show username from user table whose role is project lead from role table. userid and roleId is already in userRoles table for checking. but role table contains multiple roles and I want users only assigned as Project Lead Here is the table structure.

Project table contains LeadId which is foreign key for userid of users table. I want to insert userid into leadid through viewbag. How is this possible, any help?