Jay,
You absolutely do not need individual accounts. I have 1 escrow account that all tenants security deposits go into. (I have over 40 units). I use quick books to track it just like all of my other accounts. In the state of Pennsylvania, by law , we are supposed to give back the tenant interest earned on there money, minus a fee for us to track it. However, banks are paying such a minimum interest rate that that fee could be more that the interest earned. So we never pay it. You are overthinking this. Just keep all security deposits separate from operating account and keep track of how much each tenant has given you and you will be fine.
If a tenant moves and of course there are no charges for damage, we write a check directly from that escrow account back to the tenant. If a tenant moves and there are charges , some money may go to tenant from that account and the balance would go to our operating account for that unit and treated as income.
Hope this helps.