In the following sentence:
Landlord agress that Tenant and its guests shall be entitled to use the beach.
I know that "its guests" can modify "Tenant."
Without rewriting the sentence... could it be possible that "its guests" is modifying "Landlord" instead of "Tenant." After all, an antecedent can modify things that come before them, and since "Landlord" comes before the antecedent, it could be possible.
Am I correct? Is there a place where I could look this up?
Tenant and its guest is the compound subject in the nominal subordinate clause that follows the verb 'agrees'. In the compound, the noun phrases have equal syntactic status, and so, none of the constituent noun phrases can modify the other.
For a start, neither 'landlord' nor 'tenant', both terms denoting humans, can be referred to as 'it(s)': assuming either gender to be possible, the correct possessive form here is 'his/her'.
Rewriting it in acceptable English, then, we would get
The Landlord agrees that the Tenant and his/her guests shall be entitled to use the beach.
in which, yes, judged from a purely linguistic viewpoint, the possessive could certainly refer back to 'landlord' just as well as to 'tenants'. However, common sense would tend to indicate that the former interpretation is unlikely, to say the least!
Further, well-phrased legal language (which this patently is not!) will always take the greatest care to avoid such glaring ambiguities by repeating nouns whenever necessary (...the Tenant's guests.../the Landlord's guests...).
Incidentally, on a purely grammatical point - which may or may not be of much interest to you - pronouns do not 'modify' antecedents; they simply 'have' them.