Can Custom Pricing allow me to create private sales for a specific segment of customers who are logged into to their store account?
Yes. Bold Custom Pricing is used to offer discounted prices to specific customers only. Once a tagged member is signed in to their account, they will be able to see the prices available to them, while non-members will see the regular storefront prices only.
Read more about Custom Pricing here: https://support.boldcommerce.com/hc/en-us/articles/360040746531-Custom-Pricing-Overview-Pricing