Emu XL-7 & MP-7 User's Group

Please help me guys to pick the right one. The thing is I want the sound of
TCY and Beatgarden.
If I buy the Rom Cards and put them into XL-7s, I can use the Xl-7's Seq and
Arp.
If I buy the Orbit 3, I have 16 additional Midi channels(which I value alot)
but no onboard Arp/Seq.
Is it possible to use the XL-7s Seq/Arp on Orbit 3 sounds?

Please help me making the right decision. I'm running out of time.

THX

Kamy