Tools for managing multiple campaigns across clients?

Hi all,

This might be a stupid obvious question, but I can't work it out.

I want to do leadgen for execs to build their professional networks (targeted drips to drive scheduled meetings), so I'll be reaching *as them* (using their identity), and managing the leg work. Kind of like an EA using the boss's inbox.

A lot of tools seem to have shared inbox, and different campaign views, but don't split by client/campaign?

Lemlist (or Pipedrive) for example, it looks like I'll need 1 lemlist account per client, in order to keep client campaign views separate. Am I understanding that correctly?

What I'm looking for is like an 'agency' parent account, which I can then hang separate client/campaign inboxes from, so I can have 1 login to support multiple clients, while each client get's their own view. The client needs to see the interactions and jump in from time to time.

I'd really appreciate any tool recommendations you might have. I'm also wondering if I'm thinking about this the right way, is there a smarter way to structure this service?

Thank you!