Multiple keyboard shortcuts for the same command in OS X?

I am used to doing Ctrl-Shift-Tab to cycle through tabs.

I do slowly pick up the niceness about using Cmd-Shift-[ or ] to do the same on the Mac.

I have currently set TextMate to take Ctrl-Shift-Tab to do the tab cycling, but I'd want the Ctrl-Shift-[ or ] in addition to that to perform tab cycling. Is this possible?

The reason I ask is because I see that Chrome can do it both ways (not through any configuration of my own of course).

(I'm working at 10.11.4 environment, but I think this can work)

In my case, I have both external Screen and Keyboard (EN physical layout) attached to my MacBook Pro (ES physical layout).

Different keyboards, different keys
The thing is that the keys that I press to cycle through windows in the MacBook Cmd+§ are different from the External Keyboard Cmd+`.

So, I've forced to have two different shortcuts to achieve same action.

The solution
1. Go to: System Preferences… > Keyboard > Shortcuts (Tab) > Keyboard (section)
2. Select: Move focus to next window
3. Create: The first shortcut you prefer
4. Go to: System Preferences… > Keyboard > Shortcuts (Tab) > App Shortcuts (section)
5. Select: Finder (as target application)
6. Create: The second shortcut you prefer
7. Voilá

If in TextMate tab cycling is exposed through menu items, you can also use AppleScript and QuickSilver to add the shortcuts you need.

You can find detailed instructions in this answer for a similar question (adding a second shortcut for a command in Xcode)