Redmine

Here is my problem: I have 3 custom fields and my organisation has this maintenance project for which we need to decide the effort differences as well. We had made 3 custom fields : With(Name), With(Date), With(Time).
With has values: Client's name, My organisation's name
SO every time a ticket is raised, our requirement is to determine whether for how much time is the ticket with the client and how much time the ticket is with us.

WE have a work around so that the assigned person updates the above 3 fields everytime.
What i want to know is that can i write another update clause to update these 3 values into a completely newly created table in the same database whenever i update ticket?
In short..
Q1. Can i wirte a custom update clause just after the actual updates already being done by redmine??
Q2. If yes, where can i wirte it??
Q3. I am not interfering with redmine's flow at all. This is a seperate table with only 3 values to be updated along with a 4th column having a timestamp. Can i do this??

Thanks