It's possible to do the first part of that, but as far as I know stalemate/suddendeath option is controlled by a server variable, one that might not revert back to its normal state if you were to change its value in the map (it will revert if it's value is set up in the server.cfg).
For the first part, you will need: 2 math_counter, 3 game_round_win, 1 team_round_timer, 1 logic_compare, and the base CTF gamemode entities:
The idea is to track the scores of each team's captures with the math_counters, and then from the team_round_timer compare the two when the round ends.
You can set this up like so:
On the func_capturezone for team 1, Output of:
- OnCapture - math_counter - Add - 1
On the math_counter for team 1, Output of:
- OutValue - logic_compare - SetValue - [blank parameter override]
On the math_counter for team 2, Output of:
- OutValue - logic_compare - SetCompareValue - [blank parameter override]
On the team_round_timer, Output of:
- OnFinished - logic_compare - Compare
On the logic_compare, Outputs of:
- OnEqualTo - win_stalemate - RoundWin
- OnGreaterThan - win_red - RoundWin
- OnLessThan - win_blue - RoundWin
Keyvalues set up for the team_round_timer
Keyvalues set up for the logic_compare
Keyvalues set up for the game_round_win (this one for stalemate)
To mention a bit more about the logic_compare, there are two values it stores: a value, and a 'compare' value. You can set the compare value to something different than the value, and then compare the two with the output of Compare. You can see all the available outputs of an entity by clicking on the Help button in the property window:
Also the OutValue of a math_counter will mean that every time the value of the math_counter changes it will spit out the value to the target:
