You might consider a Connelly Concept. This is a tried and true good all around ski that you can ski easy or hard and it will progress with you. The most challenging issue will be to get something that is the correct size ski and bindings for a mix of skiers. There are probably lots of these in the used market that you could probably pick up for a reasonable price. You might check skiertoskier.com or eBay for some good deals. You may want to check the Connelly website to determine the best size for the skiers you are trying to outfit. Ski length is determined by weight and binding by shoe size. You also need to decide if you want a double boot or a rear toe kick also. Hope that helps.
1999 Prostar 205 with 330 HP LTR