[ILUG] a sorting puzzle for anybody who's interested

[Ulysees]

2 sources of plain old data
one is:                string1 dmyhhmm1 hhmm2 string3
the other is:        string1 string2 dmyhhmm1 hhmm2

I want to be able to merge them into: string1 string2 dmyhhmm1 hhmm2 string3

The following conditions are true
string1 is identical in each.
dmyhhmm1 & hhmm2 as you might have guessed are dates and times and will be
nearly identical (the hard part I think)
within a reasonable degree of certainty I can say that the combination
string1 dmyhhmm1 hhmm2  is unique and won't repeat in the data.

I'm tryin to think of the best way of doin this, the data set itself isn't
that large, about a 250k text file for each of them.
Anybody know of any nice sorting shell script that would do this ?
I'm thinking of something that takes 2 inputs and gives 3 outputs (the extra
2 are for negative matches)

Any thoughts ?

Uly