<human>: My brother (21m) "Trevor" just got engaged to his fiance (20f) "Hailey." They are planning to get married this summer and have asked me to be the best man in the wedding. We just found out today while at lunch with my brother and his fiance that they want my wife (24f) "Lisa" to be her maid of honor. I have always been really close with my brother and so naturally our SO's have gotten to know each other well. 

Now my wives sister "Jessica" (19f) is pretty pissed off about the whole thing. Her boyfriend "Mike" (21m) already has the ring and she is expecting him to pop the question any day now. She is upset because she is planning on getting married sometime this summer as well, and wanted her sister, my wife, to be her maid of honor. 

When my wife told Jessica that  Hailey had asked her to be the maid of honor, Jessica started saying that now she couldn't be her MOH because it would be look like too much of a competition and that she didn't want her wedding to come second. Jessica said that my wife wouldn't have enough time or wouldn't try as hard during Jessica's wedding on helping plan or writing a speech if she were to be MOH in two weddings. 

Either way both brides are going to be in our lives for the foreseeable future so we're trying not to step on peoples toes too hard, you know family politics.

I want to know what reddit honestly thinks about this, I tried to write this in the most neutral stance as possible but I'm sure you can tell that I'm biased that my wife would be the MOH in my brothers wedding. If this truly is a deal breaker like Jessica says, what do you think Lisa should do?

Give me the gist of the text in a nutshell
<bot>: Wife got asked, and accepted offer, to be in brother's wedding as MOH, wives sister is upset because she wanted her to be MOH in her wedding. Both weddings will be sometime this summer.