Still looking for my Half-Sisters Nesha Renee & Misti Rebecca?

I have tried the people finder sites to no avail. I am sure they have married and I haven't the foggiest idea of how to proceed. We were all born in Daytona Bch Florida. My sister Nesha Renee' is about 47 now. Misti Rebecca is about 37. Our maidens name was GEE (not pronounced like gee whiz but like McGee) We all have different mothers but the same dad. He died in 1974. I lost touch with Misti then but didn't lose touch with Nesha until 1978. The next time I saw them again was in 1986 when our big brother ped away, his name is Paul. Tried to keep in touch but letters to Misti were returned, and Nesha wrote me once but never heard from her again. We have another brother Frank who lives near me. Frank and I would both love to see the girls again. I am 50 and he is 53 and we ain't gettin any younger. Any new ideas or any help at all would be greatly appreciated.