My experience has been that unless one of the Toms are dominant, or they are following hens that are interested in your B-Mobile (never used one, I use a jake) they will hang up about 50-60 yards.

Sometimes the hens will come over to check out the tom/jake decoy and bring toms with them.

After all the birds I've had hang up on me I went to just using one or two hens. Seems to get me better results.

If you are going to use the B-Mobile I would set them up within a foot or two of each other to see if you can make that dominant tom mad.

Just my 2 cents. Good luck!