tournament creating problem

I want to create online tournament and i am thinking round robin pairing system(not hosting tour in any site but manually) but if there are more than 8/10 members i will create some small groups so that from each group top 2/3 players go final round so that players need not play huge number of games.

i) Now if there are total odd numbers of players registered in the tour like 11/17/23 .... then how can i place them in small groups because i can't divide them equally in all groups ?

ii) One issue in round robin pairing is if a player miss a game his opponent gets a valuable point for free and gets ahead. how to overcome this? not thinking swiss systems right now or where i can create swiss pairing system for free?

Thanks in advance