Copyright (c) 1998 Richard Hutnik

This game is played on the following 8x8 square board:

TURNS - At each turn, each player must move one of his stones to an (orthogonal or diagonal) adjacent empty cell or jump over any adjacent stone to the immediate empty cell (jumps are not mandatory nor multiple).
GOAL - Wins the first player to connect all six pieces orthogonally (i.e.,  it is possible to move from any stone to any other friendly stone by moving only through orthogonally adjacent friendly stones).
An example

White's turn. White must be careful here. If he moves the marked white stone he lose on the next move (Black connects all his stones with f4-e4). If d3-e2, the e3-d3 and Black wins in next move (f4-e5 or f4-e3).

Some words from the author: Groups is related to Lines of Action, with the differences being that pieces in Groups move only one space, only orthogonal connections count, there are no captures, and the game begins with a drop phase. The game also bears a resemblance to Teeko, with the movement of pieces to attain a configuration, although in Groups a winning configuration can take any form provided all pieces are orthogonally connected. [...] I had been playing it [the game with no jump rule] and found that it eventually bogged down with defensive play. I wanted to speed it up some, so I added a rule that a piece was allowed to jump over another piece to an empty space. I thought this would open the game up more. What I had found is that the game grew immensely more dynamic, and much more offensive, and finished a lot faster. What would go on from 30 turns for a game usually now finished up in under 10. The play balance seems the same now, but the game is a lot faster.

There is a ZRF to play Groups with Zillions with several other variants (including one that begins with an empty board, and player drops stones on the central 4x4 area). For more information on Groups, check Richard Hutnick's website.