What exactly do you mean by 'groups'?
You can keep honeys singly if you want - males, in particular, are territorial and would actualy preffer being alone.
However, if you want to mix the sexes, a trio would be the minnimum - 2 females, 1 male. Realy, as long as there are 2 females per male and each male has about 10 gallons to himself, the number doesn't realy matter.
If you want a single-sex group, for males, keep a minnimum of 4 in at least a 20 gallon. For females, the number matters less - as does the size of the tank - but 3 or more is best. Remember that the more gouramies there are and the more space there is for them, the less likely they are to pick one ach other incessently and stress each other out.
In practice, honeys are one of the more flexible species as they aren't too aggressive.
What size tank do you have and what other fish? What sort of group were you considering?