Multi-cam is for when you shoot one scene or moment with MULTIPLE cameras. What you are describing is a camera that shot for a long time, and broke the footage up into smaller chunks...and you want to stitch them together. P2 cameras do this, as the format of the P2 card has a 4GB limit.
If the full card structure is intact, and the camera is supported by FCP 7, and you have the LOG AND TRANSFER plugin for that camera, you simple need to use LOG AND TRANSFER and FCP will stitch those separate files into one long file when it imports.
I can't tell you what to do if I don't know what type of files these are. Are they .MXF files? Are the .MP4 files? Are they labeled MVI(number).mov? If you tell me what they are, describe the files or the file structure, I can figure out the best option.
There are only two ways to get MTS files into FCP 7. Either with Log and Transfer, and for that you need the FULL card structure from the camera, intact. Although if the AVCHD format used is a newer one, one made within the past 5 years or so, FCP 7 won't be able to import, as it was discontinued 6 years ago, and AVCHD formats are always updated.
The other option is EDITREADY from divergentmedia.com. This will convert the footage to ProRes...and MIGHT stitch the spanned clips. I haven't seen if it does that... There is a demo so worth a shot.
I can only confirm to follow Shane's advice and use EditReady to convert your footage before importing to fcp7. Go for ProRes Proxy if you're going to be using multicam angles on an iMac or lesser machine, otherwise fcp won't handle the file size smoothly and you'll go bananas.
The stitching mtx files only works with footage from Pro to Semi-Pro cameras, but expect several dropped frames here and there, I have had up to 24 dropped frames frequently, depending on the sd card speed!