I have to say, though, that if people are in social circles where such crazy ideas are seen as normal, the best thing they could possibly do is challenge those opinions.
Theoretically you're right, Time40. Trouble is that if you're a young lesbian who naturally hangs out with other lesbians, you're a focus for sexually attracted transwomen who will insist on joining any groups or social events.
Sexual orientation is pretty stable. If you were a heterosexual man pre transition you're likely to identify as a lesbian post transition. You're attracted to women but that doesn't mean that lesbians will have any interest in you. But a lot of transition is sexually motivated. TW are male, and far too often display male sexual entitlement.
Then there's the issue of validation. For many TW a sexual relationship with a lesbian is absolute proof of their womanhood.
It's an impossible situation, frankly. The only way to avoid the inevitable conflict between the two groups would be if transwomen accepted that, post transition, their pool of potential partners is going to be inevitably very small. Transsexuals seem much more willing to acknowledge this truth. The much larger group of fetishists that now sit under the trans umbrella are a different matter entirely.