Enabling the main menu for specific groups

[Little Pants]

I have a small group which I would like to limit some things for - mainly payment options. I have 3 payment options and would like to limit it to 2 options only for this group.

I can see how to limit it for the group but if I limit the  group members to that group only, the main menu doesn't enable for the  in the shop for them. The only way I can enable the main menu for that group is to also add them to the customer group, which doesn't restrict the payment method.

Does anyone know how I can enable the menu for all groups individually?

I'm also wondering if it's possible to disable certain products for a specific group.