la .xorxes. cu cusku di'e
Then we can say "su'oi ci tadni cu sruri lo dinju".
If {su'oi} is to parallel {su'o}, then I would expect {su'oi ci} to mean "at least three" as a plural quantifier.
But maybe {su'oi je ci} "at least one and three" makes sense for the exact plural 3. It's a bit hackish though, because it connects a plural with a singular quantifier.
Another option is to have a new PA that marks a PA string as plural.
And yet another option is to take plurals as the default.