The following is correct standard English:
(0) He read the poems of Catullus, Juvenal, Horace, and Virgil. He intentionally memorized only poems of the latter two.
The following uses a fantasy-word "twatter", which standard English does not contain, a single word referring back to the last two names mentioned.
(1) He read the poems of Catullus, Juvenal, Horace, and Virgil. He intentionally memorized only the twatter's poems.
The intent is that (1) be equivalent to (0). Hence the pluralized fantasized "twatter", a portmanteau of "two" and "latter".
Using the standard word "latter's" instead of "twatter's" would result in a sentence saying that "He" intentionally memorized only Virgil's poems.
Does Latin offer a mechanism like the above (invented) pluralized "twatter's", i.e., a single word referring back to the preceding two names?
Do you know a natural language which does?