I see Solong but I couldn't do much else there, if I just said "no I won't go out with your friends" I probably won't have seen her again.
The mistake is letting a woman put you into a bad position that you don't want to be in and is a lose-lose situation for you. The best that a guy can do, from what you typed, is make it clear to the woman that you want to see
just her and then give her an option of days that you could meet. The option of days is to let her adjust her schedule. If she really likes you, if possible, she will adjust her schedule to meet you and alone.
If she refuses by telling you a
lie that only meeting her in a large group of friends is possible, take that as a "I don't like you that much." or even as an insult along the lines of, "I don't really want to get to know you." Women are not usually so stupid, to the extent they don't know what is going on. When a woman subjects a guy to meeting her friends,
before you have become intimate, it's usually a type of bad female game. She will abuse the guy as entertainment for her friends or is doing other twisted stuff, like using you to make another guy in the group that is chasing her or is interested in her, become jealous. If that is not the case, women will usually tell you specifically, like- "We are going to meet my friends,
but only for a little while and just for 1 hour, because I promised. Then we will go to dinner/club/wherever after that."
And in Japan, a foreign guy needs to be very conscious that the Japanese woman he is talking to is not like beta sheeple and being
controlled by other members of the group or is desperately trying to win approval from a group (thus do anything they are told by group alphas). For example, an alpha female tells her she must meet with the group on X day or demands to see this guy that is trying to talk to her. Many beta females can be mindless in this way, where they tell too much or all of their private business to alphas in a group. Some Japanese lack the courage and ability to be independent from the group or circle they are in. So, she will ask you to meet up with her group (like bringing a sacrifice to the slaughter), and then the alpha or jealous members will rip you to shreds figuratively and verbally. They can do it directly OR behind your back style in secretive or coded conversations. And many beta Japanese girls will just stand there and let it happen or even betray you and join in on verbally shredding you. You as a foreigner, particularly if you can't speak Japanese, can be clueless as to what is going on. I've seen this happen to foreigners, way more times than I can count. It's a very sick and twisted game in Japan, where it's also done to Japanese guys outside a particular group.
So, if you can help it, don't put yourself in such bad positions. If it means not meeting her, then so be it. Because if she was really interested, she would just go see you, and not involve you in any childish or twisted group games.