Removing Date And Seconds From Cells That Include Date And Time

I have only one column (A) with thousands of cell entries. Each Cell contains a date and time. (x/xx/xxxx 12:34:56)

For example, Cell A1 = 1/24/13 18:45:22

I want the new cells to only have the time, but have the seconds removed (and not simply hide the seconds). This is because I'll need to run Conditional Formatting to find every cell with a similar time - but I only need similar times within the same minute...it doesn't matter if the seconds are off.

The new cell should just be A1 = 18:45

The real reason I need this is because I need to find every entry that has the same time (with hour and minutes), which I figure I'd use conditional formatting for. My problem is that many entries have the same time but the seconds are off.

Example:
1/22/13 12:23:11
1/24/13 18:45:22
1/24/13 18:45:36
1/26/13 22:33:41

In this example, I'd want Conditional Formatting to highlight cell A2 and A3 because they have the same time of 18:45 (not including the seconds). I figured the best way to go about this would be to remove the date and remove the seconds, and run the search that way. However, any way to accomplish goal without deleting the date and seconds would be just as useful.