Excel Formula Continuous Services Date

I’m trying to help our HR Department develop a spreadsheet to calculate continuous service dates for employees with a break in continous service, using Excel 2000.

Hire Date Term. Date
Original Hire: 9/10/1973 through 12/8/1978=
5 years, 2 months, 28 days

Rehired: 9/22/1980 throuhg 12/31/2005=
25 years, 3 months, 9 days

Here is the formula I’m using to calculate =DATEDIF(E152,F152,”y”) & ” years, ” &DATEDIF(E152,F152,”ym”) & ” months, ” &DATEDIF(E152,F152,”md”) & ” days”.

My problem is when an employee leaves and then comes back as in the above example. I’m not able to get the two to sum, to give me a total continuous service date. Any help would be most appreciated. An example spreasheet is attached.
Thanks,
Paul (bridgesp@rtpatlanta.com)