Sibling text group

Due to the need for my siblings and I to have a group text to keep track of how my mom is doing, depending on who is taking the shift flavors the updates. I have a sibling who is using this feed as a place to bring drama which has always been her role in our family of origin. With SCS I have less patience for this ( the good news is I no longer buy into it and add to it). Giving the pandemic this sister is now on duty with my mom for the long haul. I am feeling triggered by her multiple updates and digs at my mom and acylates for herself. However, this is her relationship with mom mom, always will be. When the rest of us have our weeks with mom we just give one short nightly update. The problem is my brother’s wife is close to this sister and much like her and so she sends texts to encourage my sister to keep up these 3-4 x day monologues. Part of me wants to say can we please limit these updates to once a day but my sister and sister in law will take offense and start a whole new line of drama around it. I am cofused if I should make a request ( which is trying to control their behavior) or find a way to have better thoughts so I am not triggered 3-4 x a day. I am thinking that will be your advice. I feel my silence in not responding to anything is a way for me to stay authentic in that I am encouraging her or giving her a message that I like it. But then I also feel if I don’t acknowledge it with an emoji I am being rude. I know it is hard to have the role of communicator the weeks when I pull my shifts. You never can please anyone when you are part if a big family. Problem is my sister is emeshed with my mom and much of their bonding over the years comes from talking negatively about family members behind their backs and or ganging up together to “ give honest feedback because they are not superficial people”. They justify their behavior as “helpful things people need to hear”. They will never change but can you help me make some models to change my response to it? Thank you. Happy quarantine fellow SCS. Stay healthy! ❤️