Unfortunately the tutors aren't as understanding when you submit work with a dirty great ugly border around your work.
If your uni has ArchiCAD (which it should) it will print border-less.
You can also output an oversize A4 as a .pdf and delete the border in photoshop.
Of course, I never do this
To do a multi-page spread:
1. Change your Master page size to A2 or A1.
2. Centre your drawing on the larger sheet.
3. Choose to print on A4 size.
4. Under print options select the centre anchor point and take note of the page print order (bottom left of dialog).
5. Only print this page (e.g. 5 to 5).
Does this get rid of the border? I don't know 'cause I never do it - but that's how you do a multi-page spread