how to link bones in many objects

Hi, here picture, i want to merge UMA_Male_Rig on avatar with UMA_Male_Rig in jeans, its have the same structure, size, and vectors. Underlined picture have skinned mesh rendered linked with bones (eyes, legs tors etc have linked with rigs on avatar, jeans skinned mesh have linked with bones on jeans object), I would like to scale avatar, and when link will be merged jeans will be also scaled, for example when i set more size legs jeans also will grow up. Thank for help