Need ability to connect to different LU_GROUP based on 
parameter passed in from appliation co-server.

You need to allocate the LU_GROUP's first, so that:

LU_GROUP_1         1..50

Becomes:

LU_GROUP_1         1..25
LU_GROUP_2         26..50

(this is in the Admin Console Settings) -- now you have a 
bank of 25 sessions for LU_GROUP_1 and 25 sessions for 
LU_GROUP_2, so that your session pooling works for two 
distinct hosts.

Once you have that set-up, you can then pass in the "host" 
parameter (or whatever), like

<CFX_Surfer GetInfo
  Transaction="get/info"
  host="sales"
  custnum=#custnum#>
...

<tesection GetInfo
  when tranpath_1 is "get"
   and tranpath_2 is "info">
<teif web.host=="sales">
 <teaction connect "lu_group_1">
<teelse>
 <teaction connect "lu_group_2">
</teif>
...

</tesection>