Assign APM Remote Desktop resource from an iRule

Currently we allow users up to 9 different RDP connections predefined on the APM. We assign all 9 to each user with a session variable indicating the machine name. We parse an AD attribute to get the machine names in an iRule. Problem is not everyone has 9 machines so some are blank. This results with extraneous errors on logon in the log indicating that it was unable to DNS resolve the blanks or none. This also adds to time before the webtop is displayed as for each failed lookup can take between 1 ms up to 5 secs.

Since we are already processing the machine names in an iRule is there a way to assign the Remote Desktop resource in the same iRule?

A less elegant solution we are looking at is to set a session variable counting the number or RDP resources for each user and on the Full Resource Assign creating 9 conditional statements checking session.rdpnumber = 1 session.rdpnumber = 2 ....all the way up to 9.

It would be so much easier and dynamic if we could assign resources from an iRule.

Any assistance is appreciated.