Each Gmail account has ONE main default calendar associated with it. You can however, in settings, share your calendar with another gmail account, and then change the color of each calendar.
IE: on my gmail calendar, I have it shared with my wife. My events are grey, hers or purple, my daughter (who has gmal) is green, and my work gmail is blue and my Microsoft Exchange is red. Since these are ALL part of my gmail, when you set up calwidget, they will all show up as calendars that you can either show or hide. As I said, I use google sync to get my miscrosoft events into google, but hid the microsoft calender in widget or it would show doulbe events.
You can have calwidget display the factory colors of the calendars so one could set one office as one color and the other as another.
However, as long as you set up the calendars in google to give each other complete control, one can log into either one to change any event no matter which one they were in when it was set.
IE: my wife makes an appt. Shows up on my droid. I edit the appt and change the time. Changes it on my calendar (as her event) and it changes it on her google calendar. (all done in settings).
Sorry this was so wordy but is gets a little confusing on how they all show up and sync...imagine now trying to sync this with Mac iCal, and then your kids iTouch, since mac and google don't like each other...actualy can be done for others who are interested in making google the default calendar on iTouch...tricky, but works flawlessly.