Sales Rep Function

I would like to have a sales rep function - it this possible?

Essentially I’m creating another store front as a B2B portal for our retailers to place orders with us. With a bit of editing I can cut the look down to something simple close to a traditional order form. So a retailer can tick off and request quantities of stock and send the order through to us.

It gets a bit tricky as we have sales reps that visit stores and can place orders on their behalf. How could one integrate this into our site? I want to keep the process as simple as possible (sales rep might look after a certain number of stores) and I don’t want to expose them too much to the backend or have too much control.

Thoughts? Existing addons? or a gigantic task for a developer to make?

(shipping and payments are another matter - some stores have accounts and some are on prepayment - it’s gets a little complicated).