Advice for part/assembly designing

Hello, we are in the middle of migrating from autocad to solidworks (and epdm)

Previusly we made every drawing manually and now we have some problems trying to implement a good workflow introducing some "smart" in our design process (to reduce projects times)

This is one a little insidius:

We made small gates, grouped in a assembly files composed by Column-gate-column combinations. Each of the elements (columns / gates) are assemblys with multiple configurations (example we have ColumnA composed with ColumnA element and AccessoriesA, ColumnA element and AccessoriesB, columnB with AccessoriesA and so on)

We deploy ~10-100 of this assembly in a standard project. The problem is this:

each gates have a range of lenght (for example Gate1 could be from 500mm to 700mm, Gate2 700-900mm and so on). We import the whole assembly file in the project but we cannot made it extend becouse it's fixed and we can have multiple Gate1 in a drawing, so if i change the Gate1 assembly to fit a gap of 650 mm for example, all the Gate1 files where updated and maybe in others places in the project the Gate1 visually go in interference with other objects.

I really don't want to virtualized each assembly into the main assembly drawing to get them right-displaying.

Any hint?

SolidworksAssemblies