GDD\((n, 2, 4; \lambda_1, \lambda_2)\) with Equal Number of Blocks of Three

Recently GDDs with two groups and block size four were studied in a paper where the authors constructed two families out of four possible cases with an equal number of even, odd, and group blocks. In this paper, we prove partial existence of one of the two remaining families, namely \(GDD(11t + 1, 2,4; 11t +1, 7t)\), with 7 \(\nmid \)(11t+ 1). In addition, we show a useful construction of \(GDD(6t+ 4, 2, 4; 2, 3)\).