Enable only molotov damage for teammates and block everything else.
https://forums.alliedmods.net/showthread.php?p=2681947
mp_friendlyfire 1
ff_damage_reduction_bullets 0.33
ff_damage_reduction_grenade 0.85
ff_damage_reduction_grenade_self 1
ff_damage_reduction_other 0.4
The ff_ convars can be changed as you want, but be sure the friendly fire still works. On default casual gamemode, mp_friendlyfire is enabled and all ff_ convars on 0. Even with mp_friendlyfire enabled, friendly fire doesn't work.