Ok here. If your doing ground units and you want it to be followed under by an air unit or something, here's what you do.
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Make your 2x2 Location and label it 'Isolated'. We will use this Location for two things: one, for moving your unit to an area so it won't interfere with grid set up; and two, "teleporting" your unit. Now. Create your grid locations. Make 8 1x1 Locations (Doesn't exactly matter what size but keep them small) and label them this: NE, N, NW, W, SW, S, SE, E. Assuming you know the abbreviations for cardinal compass directions, you should be fine. Now. Create a larger location where your "grid" will be set up. Make sure that it is large enough to accomodate all 8 of your "direction" locations and label it 'Grid'. Somewhere along the lines of 5x5 should be good if you want to keep them small. Now, put your rotating unit and the air unit on the map. Also, on the bottom-left hand corner of the map, with terrain the terrain under it at least 2x2 units, put a burrowed hero zergling (You'll find out what this is for later).
TRIGGERS:
TRIGGER ONE (SETTING UP GRID)
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CONDITIONS:
- Current Player brings exactly '0' 'air units' to 'Isolated'
ACTIONS:
- Center Location 'Isolated' on 'Zerg Devouring One (Burrowed Zergling' at 'Anywhere' owned by 'Owner'
- Remove 'Zerg Devouring One' at 'Isolated' for 'Owner'
- Move 'Ground Unit' to 'Isolated' for 'Current Player'
- Move Location 'Isolated' on 'Air Unit' owned by 'Current Player' at 'Anywhere'
- Create '1' 'Terran Missle Turret' for 'Current Player' at 'Isolated'
- Move Location 'Grid' on 'Terran Missle Turret' owned by 'Current Player' at 'Anywhere'
- Remove 'all' 'Terran Missle Turret' owned by 'Current Player' at 'Grid'
- GRID SYSTEM TRIGGERS
- Move Location 'Isolated' on 'Ground Unit' owned by 'Current Player' at 'Anywhere'
- Move '1' 'Ground Unit' owned by 'Current Player' at 'Isolated' to 'Grid'
- Create '1' 'Devouring One' for 'Owner' at 'Isolated' 'Apply Properties (Burrowed/Invincible)'
- Move Location 'Isolated' on 'Ground Unit' owned by 'Current Player' at 'Anywhere'
- Move '1' 'Air Unit' owned by 'Current Player' 'to 'Isolated'
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
Now that should be a very long trigger. There should be no waits anywhere. That was the hard part. Assuming you know (U)Bolt_Head's Rotating Trigger, we're going to split it into 8 different triggers.
TRIGGER SET TWO (CARDINAL CLOCK-WISE) "This is multiple triggers"
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CONDITIONS:
- 'Current Player' suffers 'exactly' '1' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for North.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '3' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for North-West.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '5' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for West.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '7' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for South-West.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '9' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for South.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '11' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for South-East.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '13' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for East.
- 'Add' '1' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
CONDITIONS:
- 'Current Player' suffers 'exactly' '15' death of 'HATCH (UNUSED)'
ACTIONS:
- First Cardinal Movement for North-East.
- 'Set' '0' deaths for 'HATCH (UNUSED)' for 'Current Player'
- Preserve Trigger
Hope that helps.
EDIT: If this ain't what you're looking for. It might help some others.

Spent a lot of time writing that up.