[Feature Request] Add per-subscription-group sorting for test results

[Ahmad-2213]

Hello There!
Problem:
Right now, when you test the real delay (ping) for servers in one subscription group and then sort the list by test results, it affects all subscription groups — not just the one you tested.

If other groups already have old test results (from previous tests), those groups also get re-sorted based on those old numbers.
If other groups have no test results yet, they stay unsorted (which is fine).

This means you can't sort just one specific group without accidentally messing up the order of other groups that you already tested and want to keep as-is.
What I want (suggested improvement):
Please add an option to make sorting by test results work only within the current subscription group (per-group sorting).
That way:

When I test and sort inside Group A → only Group A's servers are sorted by their fresh results.
Other groups (like Group B, C, etc.) keep their previous order and are not touched — even if they have old test results saved.

This would give users more control, especially when managing multiple subscriptions and wanting to keep some groups sorted one way while freshly sorting others.
Thanks for considering this! It would make working with many subscription groups much more convenient.