The answer to this will depend, at least in its specifics, on the kind of business that you run. There are general rules for which employees must be paid overtime, but we cannot be completely specific. In general, the people who must be paid overtime are all those people who do not do jobs that are supervisory or which involve a great deal of policy-making.
This may sound like an easy distinction to make, but it is not necessarily so. In many cases, an employee’s duties might include some duties that would seem to make them exempt from overtime pay. What must then be determined is what sort of duties constitute that employee’s primary duties. What we have to determine, then, is which of our employees are mainly involved with things like creating policy or interpreting it, with supervising other employees, or with exercising discretion on important matters of policy.
In general, then, the more responsible a position is, in terms of making policy and important decisions, the less likely it is that that employee will be entitled to overtime pay.