As long as you have the Pyrovision goggles, you can get this achievement alone with commands.
Be sure to equip the item on your loadout. For this example, we'll use the Pyro.
Step 1: Start by loading the map "itemtest" using the "Create server" menu or with the following game command:
Choose RED team, then Pyro with the Pyrovision goggles.
Step 2: In order to have five teammates in the RED team without anybody in the BLU team, you must disable the unbalance limit using this command:
Step 3: Execute the following command five times to spawn five RED Pyros:
sv_cheats 1; bot -team red -class pyro; sv_cheats 0
Step 4: To make the bots have the same loadout than you, type the following command:
sv_cheats 1;bot_mirror bot01;bot_mirror bot02;bot_mirror bot03;bot_mirror bot04;bot_mirror bot05;sv_cheats 0
(where Bot01 to Bot05 are the bots' names)
Step 5: To unlock the achievement, you simply have to kill yourself and respawn using this command:
Please let me know if it that worked for you.