An open letter to Eva Jackson of the United States Postal Service, senators and congressmen:     In a followup of the article in the Peninsula Beacon (“USPS again eyes Midway Post Office for closure,” Dec. 15, Page 1) in regard to the Midway Post Office on Midway Drive, we request your attention.  With the USPS acknowledgment of “underutilization” of this site and the “need to reduce its operating costs,” the Peninsula Woman’s Club strongly urges your interceding in achieving the USPS goal [of fiscal solvency].  Yes, we do wish to maintain the “retail operation” of the post office at this site, including the existing amenities, but no processing or storage functions. We encourage the cutback in days and hours, if necessary, for this to happen.   Ruth Sewell Project coordinator, Peninsula Woman’s Club Point Loma