Help forming a group of units!

[DSM]

ok what i am looking for is a way to make it when a unit owns surten item i can form a group of units that can be picked....i want a system kinda like the one off of "Broken Alliance" i want it to have the ability to call units that is picked from the holder of the item to fall in on the unit makeing a formation...also giveing a bonus if possible of the unit type....say (Hero Archer) wields group 1 flag....any units that is archer gets a range boost...idk any help?