Assuming Book2.xls is simultaneously open

In Book1.xls,

instead of using this kind of normal link formula
in say Sheet1's A1:
=IF([Book2]Sheet1!A1="","",[Book2]Sheet1!A1)
with A1 copied across and down

use instead in A1:
=IF(OFFSET([Book2]Sheet1!$A$1,ROW(A1)-1,COLUMN(A1)-1)=0,"",OFFSET([Book2]Sheet1!$A$1,ROW(A1)-1,COLUMN(A1)-1))

Copy A1 across and down to return the same linkages as the former but with
the added flexibility that any new row insertions in Book2's Sheet1 (within
the linked area) will now be reflected. Test it out and see for yourself.

Note that Book2 must be simultaneously open for OFFSET to work.