The main objective is to prioritize all openings. Identify those positions that are integral to the success of the current organizational goals. In a time of "hunkering down," very few openings that meet future needs should be at the top of this list.
This usually means not hiring additional resources in existing roles (e.g., another accounts payable clerk, another product manager). Therefore, the incumbents are asked to do more. This additional workload should be offset by adding special incentives such as spot bonuses or above-average merit increases for those affected. This extra expense is still much less than the cost of adding employees.
Internal communication is critical as a source of acknowledging the issue and what employees are experiencing. In other words, not talking about it creates hard feelings, and employees will only complain more.
Bottom line: Be sure you are taking care of existing employees who are key to the organization. At the same time, during this type of push/pull condition, candidates seem to become more prolific for those openings that are identified as priorities.
This is pretty basic, but I believe it's a discipline that many organizations lose sight of during these types of conditions. The success I have experienced has not been so much through unique and "cute" programs as through solid focus and management.