We made a game in our group to send applications to discord.
Basiclly, you fill out some stuff in the game, click done and it goes to our discord.
The problem is, that people want ranks instantly after they join the group.
Is it possible to make the game accessable ONLY if you are in the group for at least a month?
I don’t know that but It could be possible to do It with another scripting language or by using HttpService In an way that you could benefit of It.
I don’t think that Roblox stores any data about when someone joined a group so I would make a bot that accepts people into the group and in some database it stores information about when the person joined the group. Then in the game you would be able to download that data from your external server.
One thing you could do, is make a group role that you change when a user is there for a certain period of time. This could get unmanageable if your game has more than 200/500 players online at one time though.
You would either need to hire a team of people to manage the group, or as @Kacper said, make a bot to store data about when users joined.
Hope this helps you, and I hope you get this figured out!
Good luck.