The words quoted are yo (relative pronoun) + a.t.thabbidho "of eight kinds"
+ ariyapuggala+sa.ngha (the sa.gha of noble beings or persos)+se.t.tho
"best, excellent" i.e. put together the best of the sa.ngha of noble
beings." The sentence seems to be incomplete.
May I appeal to some kind Pali scholar to help me in analyzing this
word. It comes from the daily evening sa.nghaabhigiiti puja performed
in the Thai tradition.
The entire line is "yo.t.thabbidho ariyapuggalasa.nghase.t.tho"
which is translated as "The field of the Sangha formed of eight kinds
of noble beings" in the Chanting Book from Amaravati monastery,
England.