This is a hard thing, because we are so often afraid that we are going to be rude, or to hurt someone's feelings. But sometimes we need to pretend that we are from New Jersey, and just blurt it out. <g> Depending on the amount of pressure that they are bringing to bear, you might need to get rude. But start out as politely as you can.
I would do this in just the same way that I would refuse anything else I wasn't interested in. I'd simply say, "I really enjoy our discussions, and it's very flattering to be invited to join your group; but I'm sorry, I'm not interested in joining anything now. Let's just keep talking about what we do, instead." or words to that effect.
Then, if they aren't willing to take "no" for an answer, you might need to be firmer. It might come to the point where you have to point out that you are not members of the same religion. Close, but no cigar. Wiccans and Druids have a bunch of things in common, but not everything! <g>
If they still try to force you to join, you might want to point out to the Wiccan that it's against the principles of her religion to force people to do things. You might want to bring this up in one of your discussions. Ask it as a question first, "Do you guys think it's OK to force people to do stuff?"
If she says, "Only for their own good." then ask her how she can tell. (And recommend that she read my book, "When, Why ...If."<g>) If she assumes omnipotence, I'd run away if I were you.
I'd use similar tactics to deal with the other one.
If all else fails, you can always "vote with your feet" and break off your association with them. I would do that, as painful as it would be, before I'd let someone force (or coerce) me down a path that didn't seem right to me.
It would be nice if we could all be friends all the time, but that isn't always possible.
The other thing that you might try (if you would like to join a group at all, which I realize may not be the case; and if you are happier being solitary, then don't let anyone budge you) is to find a group of Druids in your area. Perhaps if you belonged to a different group, they might let you be; and this would at least be a group of people on the same path that you are on.
The ADF (Ár nDraíocht Féin / A Druid Fellowship) has a website, which lists groves by geographical location. Or you can visit the site for The Order of Bards, Ovates and Druids (OBOD) which has a wealth of links to other things Celtic and Druidical.
Good luck, and I sincerely hope that your two friends will understand, and you will all be able to remain friends!
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