hidden "combos"

[mischmi]

please list all combos of tech like

orbital defence with forward fleet lets you
build an orbital energy beam array with cruisers.

Thats important to know in early stage because otherwise a player will destroy your outpost and build a fleet of these arrays afterwards with just cruisers. And its cost many ressources to get them back or is impossible if more than one is build at each planet. And it seems the cruisers get converted in no time??!