Please Help To Solve My Problem

PHP

I Have 6 Textbox and 1 ok button. 6 Textbox to Add the 6 Team Name. Each Team Name In String(Like- A,B,C,D,E,F) When I Add This Six Team Name In Six Text Box Then I Will Click On Ok Button. When I Press OK Button Then Cricket Match Schedule Will Be Generated automatically. On Match Schedule Each Team Play Only One Match With All Team When One Team Play Second Match With Same Team Then Generate The Error...

EXAMPLE: A Team Play With B Team when A Team Play With B Team Again Then Generate Error.

I Am Solve This Problem With If...Else If...Else Statement But When the More Team Are There Then It's Large Codding

So I Need To Help To Another Way To Do That.....