Is there something similar to the concept of "issue subtype"

[Joan Andreu Juan Torrens]

I'd like to categotize the issues of a project by a subtype. I do not want to creat "subtasks" but a category of every issue where the value depends on the issue type. 

Example:

Issue type A - can be one of those subtypes: 1, 2, 3

Issue type B - similar: 1, 2

Issue type C - 1, 2, 3, 4

So when I create an issue I have to say the type & subtype of the issue 

Examples:

ISSUE-1 A.1

ISSUE-2 C.4

ISSUE-3 A.2

ISSUE-4 B.2

...

How can I implement this?

Thanks a lot !

[Nic Brough -Adaptavist- · Accepted solution]

Not really.  An issue type is an issue type.  That's it.

You can stick a field on the issues for the subtype if you want, and maybe give it different contexts so you get different options by the main type.  Or maybe use a behaviour (ScriptRunner add-on) to change the possible options in the list by type.  Or bury it in the name, so your issue type list is not A, B, C, but A1, A2, A3, B1, B2, etc