Doing it for themselves
In “Fringe Benefits,” a sixth-season “Dallas” episode, Sue Ellen and Pam (Linda Gray, Victoria Principal) leave a dress shop together.
PAM: Have you decided on the color of your dress yet?
SUE ELLEN: Mhmm.
PAM: [Playfully] Well, you’re not going to tell me, are you?
SUE ELLEN: Well, I would like it to be a surprise. But, um…. Well, one thing I can you is it won’t be white.
PAM: Well, I can’t imagine why not. [They giggle.]
SUE ELLEN: I’m so glad you’re here with me today.
PAM: [Locks arms with her] Well, I enjoy being with you, Sue Ellen.
SUE ELLEN: Despite the rivalry between Bobby and J.R.?
PAM: [Seriously] Have you been thinking about that too?
SUE ELLEN: It’s odd how relationships change. I hated you when Bobby first brought you to Southfork.
PAM: That’s funny. You never showed it.
SUE ELLEN: [Smiles, touches Pam’s hand] But then you were so wonderful to me when J.R. and I were fighting over John Ross.
PAM: Well, I think you’d do the same thing for me.
SUE ELLEN: [Nods, smiles] I don’t want us to lose our friendship.
PAM: Well, there’s no reason for that to happen. It’s up to us.
SUE ELLEN: We have to try hard to not get into their fights.
PAM: I think it would be ironic after hating each other for so long and finally being friends that we lose our friendship over their fight.
SUE ELLEN: Well, we just have to make sure that doesn’t happen.
PAM: And I know we’ll try.
Dallas Decoder 
Of course this wouldn’t last long. They would soon be taking their husband’s sides in the fight for Ewing Oil.
That’s true, Dan, although I think they maintain some semblance of friendship throughout Pam’s duration on the show.
Oh they eventually make up again. But the fight for the company puts them at odds for a spell according to my fuzzy memory.
This scene reminds me of the short conversation Sue Ellen and Ann have as they arrive at the bridal department at Neiman’s prior to Rebecca’s wedding. Each woman is siding with her (step)son. I’m sure their friendship will be tested by the rivalry between their sons as well as the John Ross/Emma mess.
Interesting parallel. Thanks!