ok saturday i went to this hotel party in the city, As soon as i walked in i started gaming this group of jus girls, like HB7-8, So i start talking and make eye contact with this HB8, my wingman takes the others while me and her are talking, so we talk a lil and she is giving me IOI's, strong eye contact, always smiled, she started to kino me everytime she laughed, paid close attention to what i said, now when i told her "u know what? how bout we go sit on the couch over there, me feet r killing me" she told me that she can't bcuz its her friends birthday and she can't leave her group. Now how do i respond to something like that?
the way i did it was that my wingman tapped me on my shoulder then i told her can i get ur number bcuz i have to go, so i got her number and moved on to another set on the other side of the room

You should have engaged the group like : "who's the birthday girl here" and talked to them. Then you could have asked to borrow your target. This way they wouldn't cockblock and the target couldn't say no since she would have gotten the permission.

I like what Obi suggested but it really depends on the type of person you are, I personally always like the method thats the easiest, soo I would do what my friends are very good at and that is to be dominant. When she says "no I really shouldn't" just give her a confident smirk and tell her again "My feet are tired, we are sitting on that couch" and then put your arm gently on her back and bring her with you. Soo you can either engage the group and get their acceptance like Obi said. Or just demonstrate confidence and Alpha male mentality and bring her with you regardless if she should/shouldn't.