Setting up a generic OneDrive for Business account for different projects that will be accessed by multiply external users with the project login details. What can go wrong?

I have a client where all internal users have office 365 biz premium accounts and OneDrive sharing works well (no issues because its biz to biz). They upgraded from their old system which was just OneDrive personal accounts where all users internal and external to the company had free accounts and everyone was able to share without a problem.

Due to compliance and trying being more secure, i want all users to use their biz premium OneDrive accounts, i understand very well now, the problems using personal and business accounts ,local synced folders do not work.  

My question is, can i setup generic projects accounts on my clients tenancy for external designers, project managers and site managers to use at the same time, with the same login details, instead of setting up every user with their own account on my clients tenancy incurring lots of OneDrive business account costs  ?
I would like to know any pitfalls anyone know of before setting this up and purchasing licenses and start to get problems.

Thanks for your help....