Rashi citing R. Meir Shali'ach Tzibur: Like the gathering of a fisherman. He gathers fish together on a hook. So the hooks of their troops ? groups of their Kohanim who gather to go together on the road ? they murder everyone together.

Rashi: We find that Chaki is an expression of joining ? 'he may not put more than three Chaki (stitches)' (Bava Kama 119b). A comber connects the two ends of a garment when he beats it with sticks. When there is a gathering of people, it is Chever Kohanim, to murder.

Radak #1: The Yud at the end of uch'Chakei is in place of a Hei. Chakeh is Makor (like a gerund) ? they wait for someone to go on the road, to plunder him. Also Yonason translates like this ? when a person intends to camp?

Radak #2, Rav Sadya Gaon: This is like "b'Chakah He'alah" (Chabakuk 1:15). Gedudim is like "Malei Al Kol Gedosav" (Yehoshua 3:15). Just like fishermen cast hooks to draw fish from the river, and from there they trap fish, so Chever Kohanim traps people.

Malbim: Also the murder of Kohanim in Shechem was as if the Kohanim did Zimah and Zenus, like the reason why Bnei Shechem were killed in days of old. Just like a man waits and hopes, if he sees troops of Chever Kohanim going on the way to Shechem, to kill people, he thinks that it is because Anshei Shechem did Zimah, and the Kohanim have Kin'ah over Zenus, like Bnei Yakov did previously in Shechem.

Makos 10a: They used to gang up to kill, like Kohanim gang up to collect Terumah from granaries.

Radak: Kohanim of the Bamos gather to plunder passersby.

Radak citing Targum Yonasan: This is like "Chaku Li" (Tzefanyah 3:8; wait for Me).

Radak citing his father: Kohanim are officers and great people, like "u'Vnei David Kohanim Hayu" (Shmuel II, 8:18).

Makos 10a: There were also many murderers in Shechem (in the middle of Eretz Yisrael). Therefore, the Arei Miklat were denser in the middle; people in the north or south needed to go further to reach an Ir Miklat than people in the middle.

Rashi: Shechemah refers to one group.

Rashi (Bereishis 48:22): Everyone [will kill] his portion.

Radak: On the road, they unite to kill everyone. If the one whom they want to plunder will oppose them, they will kill him.

Rashi: They took counsel before gathering, to where they will go to kill and plunder.

Radak #1: They did every evil deed and abomination. This is like "Zimos Ya'atz" (Yeshayah 32:7). I.e. not only this, rather, all their deeds are Zimah.

Radak #2: Zimah is intent. Like they intended in their hearts, so they did.