Boots of Teleportation says:
Any character wearing this footwear may teleport three times per day, exactly as if he had cast the spell of the same name.
The spell says (highlighting mine):
This spell instantly transports you to a designated destination, which may be as distant as 100 miles per caster level. Interplanar travel is not possible. You can bring along objects as long as their weight doesn’t exceed your maximum load. You may also bring one additional willing Medium or smaller creature (carrying gear or objects up to its maximum load) or its equivalent (see below) per three caster levels.
Same thing with Helm of Teleportation. Both items have a CL of 9th, so that would mean 3 allies according to the spell. Do these items allow you to teleport the entire party of 4 allies (wearer / caster + 3 medium creatures) or only yourself?