PHP/MySQL help required for Freelance Manager script

Hello, I’ve purchased a project management script on codecanyon to use with my projects - [login to view URL] which requires some customization to meet my needs. Requirement: I need to have the ability to assign multiple (2 or more) clients to a single project. I need clients to use separate login credentials but have access to the project details as allocated by an admin user. Currently the script does not allow for more than one client to have access to a single project. Please also note that the invoicing should remain separate for each client. Try creating a new project when logged in as admin on the demo page. You will be given the option to assign a client to the project. The script only allows you to select 1 option. I need to be able to select multiple clients. If the above is not clear, here’s an example: Admin user creates a project called Project42. Admin user assigns the same project to two different clients Mr Smith and Mrs Jones. Both clients have visibility of Project42 and carry out the normal functions (messaging, submitting, authorising etc…). When it comes to the invoicing however, Admin user creates 2 separate invoices – InvoiceSmith (only visible to Mr Smith) and InvoiceJones (only visible to Mrs Jones). Mr Smith should not have visibility of Mrs Jones’ billing / financial transactions / invoices. What I need from you: 1. Read the Requirement above and submit your bid with appropriate timescales. 2. If awarded, I will give you my current copy of the script – you will need to install on your own server. You will not have access to my server. 3. Show me a complete & working a version of the above requirement. 4. If / when approved, I’ll release a milestone payment. 5. Submit a detailed guide on how to achieve the requirement (and the associated files). 6. I will make the necessary amendments / changes & testing on my servers. I will send a link to my website so you can follow my progress. Shouldn't take me too long - if you guide is any good :) 7. Last milestone / payment will then be released. 8. Next Requirement will then be submitted on Freelancer.