Well collegegirl there are several ways to handle this:
1. Totally refuse to live a lie. No going to meetings, no going in field service period. Ethically this is wonderful, but the consequences could be unpleasant.
2. Theocratic warfare: attend the meetings, try not to barf or display any facial expressions that may be construed as critical of the fine spiritual food being served. The safe choice, although it can be challenging and requires a fair degree of acting ability.
3. Baffle them with pure truth. For example, this could be your presentation at the door:
You: Hi! We are going door to door selling these magazines to people, and to let you know that our religion is better than yours and if you want to survive you need to join us.
Note that this presentation is simple, and can be used even if you are not familar with the contents of the current magazines you are using. Another example, making conversation after the meeting:
You: That talk was a joke. Any of my professors would have been embarrassed to give a lecture that dull. I'm sure glad I only have to come here a couple times a year when my parents drag me here.
Now I like option 3, its honest and yet you are trying to be flexible and at least try to please your parents. They will no doubt appreciate your willingness to meet them halfway like this, while respecting you for taking a stand.
No Apologies