Hi. It's often helpful to make a simple example of the kind of problem you are looking to solve. This will help other people who come across your post understand what is going on.
Consider these two simple Manipulate statements:
Manipulate[Plot[Sin[a x], {x, 0, 10}], {a, 1, 10}]
Manipulate[Plot[Exp[a x], {x, 0, 10}], {a, 1, 10}]
If I understand correctly, you would like to link them together so that the sliders in each affect each other. The easiest and cleanest way of doing this is really to combine these into one Manipulate:
Manipulate[ Column@{Plot[Sin[a x], {x, 0, 10}], Plot[Exp[a x], {x, 0, 10}]}, {a, 1, 10}]
Additionally, you use the option LocalizeVariables to have the Manipulates share the values of a:
Manipulate[Plot[Exp[a x], {x, 0, 10}], {a, 1, 10}, LocalizeVariables -> False]
Manipulate[Plot[Exp[a x], {x, 0, 10}], {a, 1, 10}, LocalizeVariables -> False]
Please note that using LocalizeVariables ->False causes the slider to control the value of a always and so can lead to some confusing situations if the option isn't used carefully. This is why I would almost never use it.
