This is the 5636th most frequent Turkish word.
partililerin
"Partililerin" means "of/related to the party members" in English.
In this sentence, 'partililerin' refers to members of a specific political party, indicating who organized the event.
Partililerin düzenlediği etkinlik çok başarılı geçti.
The event organized by the party members was very successful.
Here, 'partililerin' denotes possession or association with the flags carried, identifying them as related to the party members.
Yolda partililerin bayraklarını taşıyan bir grup gördüm.
I saw a group on the road carrying flags of the party members.
In this usage, 'partililerin' describes whom the leader belongs to, specifically the members of the political party.