Distance between EI transformers

Hi,
are there any guidelines about how close two EI transformers can be?

I plan to put 4 pcb 6VA transformers in a row.

Something like this, looked from above:
-------------------------------
pri pri pri pri
Ш Ш Ш Ш
sec sec sec sec
--------------------------------

Distance between them - 2 cm (~3/4 inch).

Are there going to be issues?
 
You could put a "flux band " round them to cancel out stray flux (copper band same orientation as the winding's then soldered .
Or an iron strap round the outside of the core doesn't cancel the stray flux but contains it.
Or again cover the transformer in a tin box -ferrous metal - IE- a "potted" transformer.