Function to show content based on eGroup membership - administrator or normal member

Function format: |EGROUP_MEMEBERSHIP_CHECK(egroup_code,username)| , where:

• egroup_code - a ke egroup code from available egroups)
• username - a username from the regsitered users

Available keywords:

• |SHOW_ONNORMAL_START_egroupcode_username|
• |SHOW_ONNORMAL_END_egroupcode_username|
• |SHOW_ONADMINISTRATOR_START_egroupcode_username|
• |SHOW_ONADMINISTRATOR_END_egroupcode_username|