Lainaus:
You can combine 2 TCX files easily in notepad - the same principle should work for 3 as well.
To combine 2 activities:
Open the TCX file of the 1st ride in notepad and delete all the tags from (and including) the <Creator xsi:type="XXXX"> tag onwards. The last tag should now be </Lap>.
For the 2nd file, copy all the tags from (and including) the first <Lap StartTime="YYYY-MM-DD..."> tag onwards, paste at the end of the 1st file and then save this as whatever name you want to call it but with the .tcx extension
So for 3 you should strip both the beginning and end tags off (as above) and paste it into a file between the first and last. I think that should work, I've not yet tried it with more than two!