Sounds like you've set up an impossible problem and then ask for a solution. If we start with the assumption that A can only survive at temperatures from -100 to -80, and B can only survive at temperatures from 50 to 100, at what temperature can both survive? The answer is clearly "none". You've defined it as impossible.

So the only options are:

1. Some sort of space suits. You rule this out, but why? Why not suppose that in this high tech society, they can make space suits that are reasonably comfortable and non-awkward.

2. They communicate electronically, by Zoom or some future equivalent. But you ruled that out too. (Seems like you deliberately set out to make the problem unsolvable.)

3. They don't occupy the same room.

3.1. Relatively low tech: They have adjoining rooms at different temperatures, atmospheres, etc, with a window between them.

3.2. They send robot avatars to a common place and talk through the robot avatars.

4. Don't make their required environments so radically different. Say that one species can live at -10 to +30 C, and another can live at -50 to +10 C, etc, so there's an area of overlap where one feels hot and the other feels cold but they can both survive.

5. You could have some metaphysical solution, like they use astral projection to send their spirits to the meeting room. That might well take the story in a very different direction, though.

Sounds like you've set up an impossible problem and then ask for a solution. If we start with the assumption that A can only survive at temperatures from -100 to -80, and B can only survive at temperatures from 50 to 100, at what temperature can both survive? The answer is clearly "none". You've defined it as impossible.

So the only options are:

1. Some sort of space suits. You rule this out, but why? Why not suppose that in this high tech society, they can make space suits that are reasonably comfortable and non-awkward.

2. They communicate electronically, by Zoom or some future equivalent. But you ruled that out too. (Seems like you deliberately set out to make the problem unsolvable.)

3. They don't occupy the same room.

3.1. Relatively low tech: They have adjoining rooms at different temperatures, atmospheres, etc, with a window between them.

3.2. They send robot avatars to a common place and talk through the robot avatars.

4. Don't make their required environments so radically different. Say that one species can live at -10 to +30 C, and another can live at -50 to +10 C, etc, so there's an area of overlap where one feels hot and the other feels cold but they can both survive.

5. You could have some metaphysical solution, like they use astral projection to send their spirits to the meeting room. That might well take the story in a very different direction, though.

** Follow on thought **

If the ranges aren't TOO far apart, the creatures might be able to put up with discomfort. Like one could say that human beings require temperatures of around 0 C to 30 C to function. But a human could SURVIVE at -20 or +50. Especially if all they have to do at the extreme temperatures, pressures, etc, is sit and talk. And now I'm thinking, What are the limits of what you could "get used to"? Like I spent most of my life in Ohio and Michigan, where temperatures tend to be cool to cold. -20 was not uncommon in Michigan. But now I live in the Philippines, where it is routinely high 20s to low 30s. And I'm getting used to it. I used to think 28 was unbearably hot. Now I think it's comfortable to maybe a bit cool. The thermometer on my desk as I type this says 29.3 and I feel quite comfortable. Could I get used to 35? Probably. 40? I'd guess not. I don't know if any studies have been done on this.