Sales force refers to a team of sales people within a company, TM'ing a generic term does not mean one has the rights to every domain. If the term was artificial such as ebay of Amazon then of course it would be a blatant infringement. In this case it is not, i would only be infringing if i offered it to the TM holder or used it to advertise products or services simular to the TM owner.
Sales Force
noun
the division of a business that is responsible for selling products or services [syn: sales department]