Splitting a file based on values next to matching pattern

I am having a file input.txt which include ~50,000 rows and ~100 column. I want to split is according to matching entry followed by the matching patter. File separator are both space and tab. input.txt #information #dateofcreation #file type AA BB CC DD EE FF GG HH II AA bb ac aD FF GG hg ad DA ga Dt pp Ee FF gg pm TT DA bR AT GT Gg FF GG Hb Yh NM gt Jh GT FF hb TH KM MM In the input file there a matching field FF in all the lines followed by the entry matches in some lines. I want to have three output file from this input file GG.txt AA BB CC DD EE FF GG HH II AA bb ac aD FF GG hg ad DA bR AT GT Gg FF GG Hb Yh gg.txt DA ga Dt pp Ee FF gg pm TT hb.txt NM gt Jh GT FF hb TH KM MM Thanks.