box 7 and box 8 on the 1098 could make a difference as far as applying all the 1098 to the same property. The ones not for the principal residence would not have box 7 marked and would not apply toward the principal residence
Unless
The principal residence is the property that is securing the mortgage for both properties. Then you legitimately may not be entitled to deduct all mortgage interest against the same property.
Please verify what the box 7 and 8 for all 1098's is showing for the property secured by all mortgages...
If the principal residence is the property securing both properties then it probably should be limited.
Please refer to IRS Publication 936 for additional information.
