Chicago Security Deposit Account Question

[David Shifirn]

I own 5 units. 

1.Do I need to keep each individual security deposit in a separate checking account?

2.3 of the units are in a 3 flat. Can I keep those together in one checking account?

"Intermingling funds" makes this confusing. No intermingling with personal money makes sense but does that mean no intermingling with other security deposits as well? Also, if you own numerous residential rentals and have to keep the deposits in individual accounts do people maintain multiple accounts at one bank? How are others handling this with multiple units?

Thank You in Advance