what are you trying to get at here?
"Making a Team"
It doesn't mean you have to have all the members in the team be in the catacomb to play the game, it is intended this way, you just have to utilize how to synchronize your team to reap the rewards for those individuals and during Events.
You take two level 55 skillers into a group run created by a level 1 character (all in the same guild) ... the skillers sit in town and mute, now the level 1 clears catacombs by him/herself and gains benefits of more monsters spawning and more drops which increase the chance of better items, also helps when clearing Objectives like Shamans, the skillers could enter and whittle down the monsters faster and tank while the creator kills the monsters off for the drops... and benefiting more.
Once the creator of the game reaches the same level as the skillers, they can then choose to enter the catacomb together and complete their run to Master Quest ... or the skillers let the other character carry on leveling up in catacomb by him/herself ... up to the Team / Party.
Would it be abusing the game if people play this way or not? As for myself, it isn't, it is just another way to play the game with more benefits.