Hello. Rather than use 'among', I would say 'by working with' because the skills you gained are a direct result of working 'with' customers or vendors. Working 'among' customers means being situated near the customers, while working 'with' them is a direct interaction. Here are some extra examples for how you might write this clearly: My four years of experience as a senior sales assistant at XXX, a subsidiary firm of XXX, enabled me to gain skills in communication, problem solving, and multitasking by working with vendors and clients. I have four years’ experience as a senior sales assistant at XXX, a subsidiary of XXX. In this role, I worked with vendors and clients, enabling me to develop strong communication, problem solving, and multitasking skills. - The second example is more active, and may be easier to read, while the first is more passive. In the second example, I've split it over two sentences for easier reading. - I've linked together the skills you've gained (communication, problem solving, multitasking) so it is easier to read. - I've also cut out the word 'customer', as customer and client might mean the same thing (depending on the context). - It may be clearer to include the name of the subsidiary firm as well as the name of the parent firm.