sum of time by group

I'm looking for a way to calculate the amount of time spent on calls by week. I have groups for week beginning on Sunday, that groups all the calls for that week - works fine. I have a summary to count the number of calls each week, but I need a way to calculate the amount of time spent on those calls that week. A summary works but I can't seem to figure out how to display it as hh:mm instead of a number? I don't want this is in the footer as it wouldn't make sense.

Right now I get
Week 1 - 15 calls 876
week 2 - 30 calls 480
Week 3 - 90 calls 1,987

I'd like it displayed as
Week 1 - 15 calls 14hrs, 36 minutes
week 2 - 30 calls 8hrs
Week 3 - 90 calls 33hrs, 7 minutes

Thanks in advance
Kevin

I use a formula to convert from seconds to hours/minutes.

totext(truncate(avgtime/3600,0),0,"")+":"+totext(truncate(avgtime/60,0)-(truncate(avgtime/3600,0)*60),"00",0,"")

Maybe not the best solution, but it works for me.

Perfect with a little tweaking I am able to get the info I needed in the format I want!

Thanks
Kevin