The beef between Xawaadle and Udejeen started when the diverse sections of Udejeen decided to partially move from Muqdisho to ancestral lands in Hiiraan. It is a typical case in which an ignorant warlord instigates war between families. I'll explain the story.
Before 1991, Udejeen lived mostly as nomads between Beledweyne to Feerfeer, the others lived in cities like Muqdisho and Beledweyne. The udejeen nomads were part of the wave of USC fighters that stormed Mogadishu after 1991, and settled in Shangaani, with own militia and an aspiring 'warlord' Eng. Cadow
Anyways, when the Udejeen decided to move back to Hiiraan, and at least built a town in Jawiil, which is basically nothing more than a small settlement which has been neglected for years, they were obstructed by the socalled governor of Hiiraan: Dabageed. It was around 2005, when there was fundraising in Europe, where the diaspora group collected around 100.000 USD for the costs of withdrawal and the immediate things people need in Jawiil. Abgal people in the diaspora wanted also to contribute to this progressive project of Udejeen, they promised they would contribute 100.000USD to kickstart the project. Unfortunately, this all was delayed by the actions of the Dabageed guy and the ensuing xawaadle attacks.
Anyways, when the first convoy of troops and people moved from Mogadishu to Jawiil, the guy Dabageed issued a 24-hour deadline for Udejeen to withdraw from Hiiraan
This famous 24-hour deadline was basically declaration of war. Udejeen diaspora group met with those in Somalia through teleconference, and told the elders still in Mogadishu to organize a Mudulood shir to discuss this coming war. At this shir, the other Mudulood sections, basically gave moral support, and I am sure they would have given more support in terms of weapons or money, but it was at a time (2006) when Mogadishu was in turbulent mood.
So when the first major engagements started in Hiiraan which was around may 2006, Abgal itself was preoccupied with the wars in Mogadishu. Since then it was basically Udejeen vs Xawaadle clans in Hiiraan and Feerfeer.
The other major engagement was in Feerfeer district around 2007, also at a time when Abgal was preoccupied with the fast changes in Mogadishu and ethiopian occupation.
To make it short: Mudulood is the only grouping in Somalia that is solid as a rock. And this unity and brotherhood will be strengthened in the coming years.