Player Model Bodygroups on Multiplayer?

How do I enable player model bodygroups on a multiplayer server?

I’m talking about when you hold C, player model and select a custom model that has bodygroups which allows you to change various features.

It doesn’t seem to work in multiplayer but works fine in singleplayer. I changed my bodygroups from the player model menu and then when I kill myself to see the changes, I’m still the same.

Does anyone know why or can help me?