Design Entry Gates with token counter and Complaint Counter

1. There are two entry gates (Entry1 and Entry2) and one token counter (T1 and T2) for each gate.

2. Customer needs to collect token from any of the token counter.

3. Unique token should be generated concurrently. For example, if counter T1 generates token number 4 and at the same time, another token is being generated from counter T2, it should be 5. There should not be any inconsistency.

4. There are two Complaint Counter (C1 and C2) and both of them have their individual display screen (D1 and D2 respectively)

5. Display screen can display at most three numbers at a time. Same token number should not be displayed in both the screen.

6. Customers with remaining tokens need to wait in Waiting area.

7. Once Complaint will be resolved for any token, Display screen will remove that number and add new token number from waiting queue.

Can anyone suggest how to design the above problem.