ICE states that Cross Trades Rule 8A.08 places restrictions and requirements on situations in which a trader may enter orders for different beneficial owners that will trade against each other (“crossing orders”). In most situations, the Rules require the inclusion of a time delay between the entry of the buy and sell orders. Orders which are immediately executable against each other do not require this time delay, provided they are entered immediately. If the orders are not immediately entered, then the required time delays must be incorporated.
The following shall apply to all transactions on the Trading System, except those conducted on or through ICE Block or other designated system.
b. Crossed Trades
(1) Independently initiated orders on opposite sides of the market for different beneficial account owners that are required to be entered into the Trading System immediately, and which are so entered, even if such orders are immediately executable against each other, may be entered without delay, provided that the orders did not involve pre-execution communications.
(2) Opposite orders for different beneficial accounts that are simultaneously placed, by a party with discretion over the orders and/or the accounts, may be entered provided that one order is exposed on the Trading System for a minimum of 5 seconds for futures contracts and a minimum of 15 seconds for options contracts.
(3) An order allowing for price and/or time discretion, if not entered immediately upon receipt, may be knowingly entered opposite a second order entered by the same entity, only if the second order has been entered immediately upon receipt and has been exposed on the Trading System for a minimum of 5 seconds for futures contracts and a minimum of 15 seconds for options contracts.
source: https://www.theice.com/publicdocs/futures_canada/rules/Rule8_Trading.pdf. Please refer to the ICE rulebook on their web page for the most current version of these rules.