Let me try.The first question is about letting go.It all begins with the individual bringing in the client.As a representative of the company,what they discuss becomes the client(s) expectation of the company.Thus,informing the client on the procedures that follow such as 'letting go' the client to other staff is necessary.If the client is appropriately informed on what to expect next it will inspire confidence and ease letting go on both parties especially because clients become attached to the individual bringing them in.

The result should be a synergy in the different stages as the clients are well informed and the staff are receiving 'processed' clients e.g. the cashier is not discussing products with the client.If the individual bringing in the clients guides them well,then all parties should have an easier time interacting with each other.A problem will arise if the client is misinformed or 'sold' something the others can't deliver.

The question about key account managers and individuals who pocket clients.This is a problem to the organization itself.As you've pointed out it kills teamwork and is usually a way for individuals to secure their importance in the organization if not engage in unscrupulous deals.

To me thats a problem with how the organization is structured and possibly the organizational culture since individual interest is superseding the co's interest.Renumeration based on clients is usually the problem.On one hand the sales team brings in the clients but on the other hand they don't finalize the proceedings.

Its a difficult problem because although an individual brings in the client,the individual processing payments or deliveries is just as important to the clients experience.The place to start would be with the people introducing the problem.Understanding their grievances and rewarding their efforts in a way that aligns their interests to the organization is the way out.Without more details on their grievances and perceived efforts,thats as far as I can go.