White Label for partner accounts

I was searching for an alternative to GoHighLevel and found SharpSpring as a CRM that could be used by agencies for a 'white label' solution for sub-accounts.  I am not seeing where I can create a customized 'portal' like described by SharpSpring.
Are there any other agencies using CC as a white label lead-gen and nurture platform?  Am I missing where this is set up? Thank you in advance for points on this.