How can I prevent a function from carrying on if the player is on the same team?

the kill function kills the player when the gui button is clicked, then "if bug" area just checks if the other player that has been hit has been "infected" then it carries out a message then carries out the other player that has been infected death

These two chunks here are relevant to a Players death. The first chunk is the function and the second chunk is the GUI, This all works fine, but I want it able to not kill a Player if the Player is on the same team.

I hope I made sense! Please help

function kill()
if bug == nil then return end
if bug:FindFirstChild("Torso") == nil then
local vCharacter = Tool.Parent
local newPlayer = game.Players:playerFromCharacter(vCharacter)
local message = Instance.new("Message")
message.Text = ""
message.Parent = newPlayer
wait(1)
message.Parent = nil
else
bug.Humanoid.Health = 0    -- This is where it kills player regardless of which team, or even if its an NPC how can I make it so it doesn't kill the people on the same team?
reset()
end
end

Below is the button that if clicked on then the function will happen.

	local button5 = Instance.new("TextButton")
	button5.Name = "Button"
	button5.Text = "Kill"
	button5.BackgroundColor3 = Color3.new(0.752941, 0.752941, 0.752941)
	button5.Size = UDim2.new(0,70,0,25)
	button5.Position = UDim2.new(0,80,0,35)
	button5.Parent = frame
	button5.MouseButton1Click:connect(function() kill() end) -- When the kill function begins

For players, you could just use an if statement that end the functions if the player's TeamColor property is equal to other player's TeamColor property.

For NPCs, it's a bit more tricky as NPCs usually don't have teams associated with them. You could perhaps add a BrickColor value called TeamColor to the NPC and make that color the infected team's color and then do an if statement that ends the function if the player's TeamColor is equal to the BrickColor value's value.

Code example:

local bugPlayer = game.Players:GetPlayerFromCharacter(bug) --Gets a player from the bug, if there is one.
if bugPlayer then --If there is a player associated with the bug, do this block of code.
	if newPlayer.TeamColor == bugPlayer.TeamColor then return end --If the newPlayer's Team is the same as the bugPlayer's team then stop the function
	--Do stuff here
else --If bug is an NPC, do this block of code instead.
	if bug:FindFirstChild("TeamColor") and bug.TeamColor.Value == newPlayer.TeamColor then return end --If the newPlayer's Team is the same as the bug's team then stop the function
	--Do stuff here
end

I hope my answer helped you. If it did, be sure to accept it.

Well, in my situation I would've placed an IntValue or NumberValue in Workspace for every team, and then I'd just make it check if it was == 1, and, if not, set it to 1, then allow the script to continue. From there, I'd end with else wait() end

This is just a simple solution to your problem

Pretty much all you gotta do is make a script that creates a NumberValue for every person that joins the game. if that person is on a certain team, a NumberValue (Let's say it's called Team) will be 1. If that person is not on that team, the value will be 0. If the value is 1, the player will be killed. If the value is 0, well the player won't die.